I, p12I, and p13II regulatory non-structural proteins. p12I resides in endomembranes and interacts with host proteins on the pathways of signal transduction, thus preventing immune responses to the virus. p8I is a proteolytic product of p12I residing in the plasma membrane, where it contributes to T-cell deactivation and participates in cellular conduits, enhancing virus transmission. p13II associates with the inner mitochondrial membrane, where it is proposed to function as a potassium channel. Potassium influx through p13II in the matrix causes membrane depolarization and triggers processes that lead to either T-cell activation or cell death through apoptosis.Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of illnesses, such as adult T-cell leukemia/lymphoma, myelopathy/tropical spastic paraparesis (a neurodegenerative disorder), and other diseases. Therefore, HTLV-1 infection is a serious public health concern. Currently, diseases caused by HTLV-1 cannot be prevented or cured. Hence, there is a pressing need to comprehensively understand the mechanisms of HTLV-1 infection and intervention in host cell physiology. HTLV-1-encoded non-structural proteins that reside and function in the cellular membranes are of particular interest, because they alter cellular components, signaling pathways, and transcriptional mechanisms. Summarized herein is the current knowledge about the functions of the membrane-associated p8 Therefg effect . R88 is y HTLV-1 .I  is a highly conserved protein  limited viral persistence  ,95 II isII may have an NLS as well, which might adopt a conformation favorable for trafficking the protein to the nucleus under conditions that mask the MTS. Thus, p13II could fulfill several cell-compartment-dependent functions; however, currently, this multi-functional role is only hypothetical [II is trafficked to and inserts into the IMM, forming predominantly helical self-assemblies with molecular weights higher than that of a monomer with cation channel activity [II is predominantly a potassium (K+) channel [p13thetical ,100. Thethetical . After iactivity ,101,102. channel ,102.II localizes in the IMM of isolated energized rat liver mitochondria and triggers K+ influx that results in modified mitochondrial morphology and swelling [II concentrations between 5 nM and 400 nM and could be reversed by adding a protonophore that collapses IMM potential (ΔΨm). Furthermore, this study showed that p13II causes IMM depolarization, which increases proton transport through the pumps of the electron transport chain (ETC) and thus restores membrane potential while increasing oxygen consumption. As a result of p13II-enhanced ETC activity, the level of reactive oxygen species (ROS)—which are produced in part in the mitochondria [II mutants with alanines instead of arginines in the MTS  compared with that associated with expression under conditions with normal glucose concentrations [An analogous effect of mitochondrial membrane depolarization, which is dependent on p13La cells . Studiesoduction . Howeveroduction , an incrarvation . The auttrations . This outrations .II activates primary T cells from their resting state, a change that depends on ROS concentration and K+ flux [II protein controls the turnover of infected T cells by eliminating those that undergo cancerous transformations while activating and promoting the division of those with regular morphology. Thus, the protein might increase the number of “normal” infected cells supporting virus proliferation and long-term persistence in HTLV-1 carriers. However, at present, the exact mechanisms through which p13II affects cell physiology and pathology are poorly understood. The existing view is that the protein acts by modulating levels of mitochondrial ROS [II in HTLV-1-infected cells assumes that the protein inserts into the IMM to form oligomeric channels. The channel activity of p13II induces a ΔΨm-dependent K+ current and membrane depolarization. This effect is probably compensated by the enhanced activity of the ETC, leading to ROS formation. As a result, T cells undergo either activation at physiological ROS concentrations or apoptosis at toxic ROS levels  and interacts with both viral and host proteins ,115. As II protein is the precursor of p13II but has entirely nuclear localization. It prevents the export of Tax/Rex mRNA from the nucleus to the cytoplasm, thus acting as a downregulator of Tax and Rex and suppressor of viral replication [II binds specifically to and forms complexes with both Tax and Rex, and these interactions are stabilized by the presence of viral mRNAs.p30lication ,116. p30I, p12II, and p13II, which function in the organelles and plasma membranes of infected cells. Current knowledge suggests that these proteins aid the virus in escaping immune surveillance through mechanisms that modify multiple signaling cascades and regulate the cell cycle by inducing cell proliferation or apoptosis. Thus, these proteins are critical to viral adaptation, long survival, and proliferation. In-depth understanding of their mechanisms remains to be accomplished, however. It is currently unknown how these proteins interact with cellular components. Furthermore, multiple functions have been proposed for each of the three proteins, but the factors determining which function is initiated at which viral stage, or whether multiple functions are fulfilled in parallel, are poorly understood. Therefore, along with in-cell studies, a detailed explanation of protein structure and mechanism at the molecular level would be particularly helpful. Specifically, in vitro studies of recombinantly produced purified p8I, p12II, and p13II, which currently are extremely limited or even nonexistent, would both provide information about the structural bases of the interactions of these proteins with host membranes and proteins and clarify how the structures and membrane environment facilitate protein functions. This knowledge would greatly expand the general understanding of HTLV-1 mechanisms and inform the development of approaches to gain control of cellular dynamics and immune responses.This review focuses on the roles of the HTLV-1-encoded regulatory NSPs p8


Crystallite aluminosilicates are inorganic microporous materials with well-defined pore-size and pore-structures, and have important industrial applications, including gas adsorption and separation, catalysis, etc. Crystallite aluminosilicates are commonly synthesized via hydrothermal processes, where the oligomerization of silicic acids is crucial. The mechanisms for the oligomerization of poly-silicic acids in neutral aqueous solution were systematically investigated by extensive first-principles-based calculations. We showed that oligomerization of poly-silicic acid molecules proceeds through the lateral attacking and simultaneously proton transfer from the approaching molecule for the formation of a 5-coordinated Si species as the transition state, resulting in the ejection of a water molecule from the formed poly-silicic acid. The barriers for this mechanism are in general more plausible than the conventional direct attacking of poly-silicic acid with reaction barriers in the range of 150–160 kJ/mol. The formation of linear or branched poly-silicic acids by intermolecular oligomerization is only slightly more plausible than the formation of cyclic poly-silicic acids via intramolecular oligomerization according to the reaction barriers (124.2–133.0 vs. 130.6–144.9 kJ/mol). The potential contributions of oligomer structures, such as the length of the linear oligomers, ring distortions and neighboring linear branches, etc., to the oligomerization were also investigated but found negligible. According to the small differences among the reaction barriers, we proposed that kinetic selectivity of the poly-silicic acids condensation would be weak in neutral aqueous solution and the formation of zeolite-like structures would be thermodynamics driven.  Zeolites are crystalline silicates with well-defined microporous structures and superior thermo- and chemo-stability. They are widely used in many industrial fields of great significance, including as porous support or catalysts in conversion of chemicals ,2,3,4,5,N2-like mechanism by directly attaching of hydroxyl of the non-protonated silicic acid to the pronated one in the reaction reverse to the protonated hydroxyl to form a 5-coordinated Si species followed by detaching of a water molecule. They also showed that the lateral attack of the hydroxyl of the non-protonated silicic acid to the pronated one nearly vertical to the direction of the detaching water is also possible but with an activation energy of 17.3 kcal/mol. Trinh et al. proposed that the reaction in basic solution initiates with deprotonated silicic acid through a 5-coordinated Si species would be more plausible, and the reaction barriers for formation and dissociation of the 5-coordinated Si species are 57 and 66 kJ/mol, respectively [N2-like mechanism where the formation of the 5-coordinated Si species and proton transfer for water formation take place simultaneously, though the proton catalyzed processes would take place with a two-step mechanism through the 5-coordinated Si species as an intermediate or a single-step mechanism as that for the neutral solution. Researchers also proposed that the oligomerization of silicic acid can be affected by several factors, such as pH, the dielectric constant of the reaction mixture, etc. Tossell investigated the free energy change for the oligomerization of silicic acid with advanced quantum mechanics techniques and found that condensation in water is weakly endothermic and the reaction may prefer to take place at elevated temperature and pressure in a solution with low dielectric constant [- and they showed that water adsorbs firstly at one of the Si atoms for the formation of a 5-coordinated Si species with a barrier of 79 kJ/mol, which dissociates into two silicic acid molecules by crossing a barrier of 19 kJ/mol [Considerable theoretical efforts have been put to understand the oligomerization of silicic acids ,25. The ectively . They alectively . This meectively ,32. Thomectively . They coconstant . Mora-Foconstant ,36. Whitconstant . People 9 kJ/mol . Pelmens9 kJ/mol  and Cris9 kJ/mol  investig9 kJ/mol ,42,43,44It is generally believed that oligomerization of silicic acid during the hydrothermal process is crucial for nucleation and growth of the zeolite framework . Due to In general, the nucleation and growth of zeolites and colloidal silica can be considered as oligomerization reactions among poly-silicic acid molecules. The processes can be described by networks of condensation reactions among monomers and oligomers of ortho-silicic acid. We firstly investigated the dimerization of ortho-silicic acid . 2O (−19 kJ/mol). In this structure, the O1–H2 distance is 1.81 Å and is typical for a strong hydrogen bond. The O2–H2 distance is 0.99 Å corresponding to a hydrogen-bond distorted Si–OH. Then, the reaction may proceed with a proton transfer from O2 to O1 accompanying the attacking of O2 to Si1 leading to the formation of the transition state . The calculated reaction barrier compares well with that reported by Trinh et al. [−1. After the transition state, proton transfer of H2 from O2 to O1 may take place, and the formed H2O is detached and bonds the dimer with hydrogen bond  of each reaction was calculated as the difference in electronic energy between the reactant and transition state. The free energy change (ΔG) of each reaction was calculated as the difference in free energy between the reactant and the product and includes the contribution from electronic, rotational, vibrational and transitional partition functions, and solvation, using standard statistical mechanics methods at 298 K and 450 K [2O and silicic acid may overlap.First-principles-based calculations were carried out to investigate the oligomerization mechanism of poly-silicic acid containing less than nine Si atoms. The calculations were performed with the generalized gradient approximation (GGA) functional developed by Becke, Lee, Yang and Parr (BLYP) ,53 and f3 code ,55. The 3 code ,57,58. Gulations . The enend 450 K . We estiThe oligomerization of silicic acids is crucial for the nucleation and growth of zeolites from the reaction mixture during the hydrothermal process. By using a neutral aqueous solution as a model system, the mechanisms for the condensation of silicic acids were systematically investigated by extensive first-principles-based calculations. We showed that silicic acid oligomerization proceeds through the lateral attacking and simultaneous proton transfer from the approaching silicic acid for the formation of a 5-coordinated Si species resulting in the formation of a water molecule that detaches from the poly-silicic acid. The barriers for this mechanism are in general more plausible than the conventional direct attacking of silicic acid with reaction barriers in the range of 150–160 kJ/mol. The formation of linear or branched poly-silicic acids by intermolecular oligomerization is only slightly more plausible than the formation of cyclic poly-silicic acids via intramolecular condensation according to the reaction barriers (124.2–133.0 vs. 130.6–144.9 kJ/mol). The potential contributions of oligomer structures, such as the length of the linear oligomers, ring distortions, and neighboring linear branches, etc., to the oligomerization were also investigated but found negligible. The small enthalpy and free energy change and the small differences among the reaction barriers for the oligomerizations indicate that these reactions would be in equilibrium, the kinetic selectivity of the poly-silicic acids oligomerization would be weak in neutral aqueous solution and the formation of crystalline silicate structures would be thermodynamics-driven.


O-GlcNAcylation is an important posttranslational modification governed by a single pair of enzymes–O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). These two enzymes mediate the dynamic cycling of O-GlcNAcylation on a wide variety of cytosolic, nuclear and mitochondrial proteins in a nutrient- and stress-responsive fashion. While cellular functions of O-GlcNAcylation have been emerging, little is known regarding the precise mechanisms how the enzyme pair senses the environmental cues to elicit molecular and physiological changes. In this review, we discuss how the OGT/OGA pair acts as a metabolic sensor that integrates signaling pathways, given their capability of receiving signaling inputs from various partners, targeting multiple substrates with spatiotemporal specificity and translocating to different parts of the cell. We also discuss how the pair maintains homeostatic signaling within the cell and its physiological relevance. A better understanding of the mechanisms of OGT/OGA action would enable us to derive therapeutic benefits of resetting cellular O-GlcNAc levels within an optimal range. Proteins are extensively post-translationally modified, with over 450 different types of posttranslational modifications (PTM) that play important roles in cellular signaling, protein-protein interactions or modulation of gene expression . The avaogt and oga gene causes early postnatal lethality in mammals  which integrates amino acid, carbohydrate, fatty acid, nucleotide, and energy metabolism Figure . The HBP mammals , 11.Remarkable progress in understanding the signaling properties of O-GlcNAcylation has suggested that O-GlcNAcylation and the OGT/OGA enzyme pair may play a key regulatory role in coordinating cellular signaling . In thisTraditionally, intracellular signaling has been thought of as linear modules of signaling architecture, from activation of receptors via ligands to information flow through phosphorylation cascades and subsequent activation of transcription and protein synthesis. However, recent advances in mass spectrometry and proteomics have allowed a more holistic assessment of protein and lipid modifications that result from singular events, and the results have indicated that a single stimulus could result in complex responses with multiple pathways being activated simultaneously with feedback loops and cross-talks in place , 13. TheA simple way to re-think about signaling proteins and their organization would be to identify key signaling hubs, termed “integrators.” A signaling integrator within the cellular environment could be defined as a protein complex which could receive multiple forms of inputs from other signaling molecules, elicit multiple outputs simultaneously with spatiotemporal control and the ability to reset itself in a timely fashion. Its role would be critical in allowing quick coordination of the activity of several signaling modalities and modulating their signaling dynamics to provide a homeostatic balance or amplification of signaling intensity. While the idea that several signals converge on a specific substrate to elicit defined biological events is a common theme in cellular regulation, the existing ideas prevalent in the field focusses primarily on specific activities of effectors downstream and is limited on the scale of proteome involved. Ideally, the most effective and efficient signal integration would be able to take place almost instantly, allowing the cells to effect quick responses upon gathering external stimuli via global modification and activation of proteins and genetic machinery. The OGT/OGA signaling complex possesses the above-mentioned characteristics that allow them to be an ideal integrator of signaling inputs within cells.While the substrate of OGT, UDP-GlcNAc, integrates information about nutrient flux within the cell, OGT and OGA are also uniquely positioned to receive information from several key nutrient-sensitive signaling pathways and appropriately transduce this information.One of the prevailing views in the field is that OGT makes use of its N-terminal tetratricopeptide repeats (TPR) domain, which is an extended superhelical structure of up to 13.5 TPRs, to act as a scaffold for interacting substrates . BesidesAMPK is an energy sensor that maintains cellular energy level with regard to cellular stress and nutrient availability. Upon its activation, AMPK phosphorylates OGT at threonine 444, resulting in the dissociation of OGT from the chromatin and inhibition of gene expression. Conversely, OGT could mediate O-GlcNAcylation of AMPK, and positively regulate AMPK activity through its phosphorylation at threonine 172 , 16. Glu3) while not possessing the pleckstrin-homology domain like PDK1 and AKT, suggesting different binding affinity toward PIP3 production  has been established to be a stress sensor . Upon gepoptosis . A recenpoptosis .Upon glucose deprivation, chromatin-associated fumarase (FH) is phosphorylated by AMPK at Ser 75, which triggers its association with ATF2 and facilitates gene expression for cell growth arrest . In cancThe Hippo/YAP pathway controls organ size in animals and its dysregulation results in cancer . Under gOga knockout models, anatomical defects include delayed brain differentiation and neurogenesis with pronounced changes in expression of pluripotency markers (O-GlcNAcylation has been known to regulate the activity of proteins involved in embryonic stem cell (ESC) pluripotency and differentiation, such as SOX2 and OCT4 . It has  markers . These sFor comprehensive integration of signals coming from different signaling partners, timing is an important aspect that is gradually recognized to be extremely important for signal transduction. One important feature of PTMs is that they should enable cells to respond quickly to cues in a reversible fashion, and that these signals could be defined for their intensity and duration Figure . ProteinSome studies have indicated the dynamic changes of O-GlcNAcylation during insulin signaling , 23, lymOther than short-term regulation, O-GlcNAcylation can result in long-term changes within the cell, which has been elaborated in many previous reviews , 29, 46.3 production , mitochondrial OGT(mOGT) and short form OGT(sOGT). The longest OGT isoform, ncOGT, is mostly localized in the nucleus but is able to shuttle toward the cytoplasm and plasma membrane in response to signaling cues , 47 Fig. One prioduction . OGT is oduction . The mecoduction . The abiIn vitro experiments indicate that sOGA exhibits lower enzymatic activity compared to OGA  and the reverse reaction driven by OGA (denoted as k−1)  Figure . This eq Figures , 2B.Given that O-GlcNAcylation levels of specific proteins may not be linearly correlated with nutrient availability, the expression and activity of OGT and OGA have to be tightly regulated. The observation that the levels of OGT and OGA transcripts and proteins fluctuate in many processes, such as cell cycle progression, stress response and tissue development, hint at the intricacies of this regulatory machinery at work , 66.Oga gene is situated within the highly conserved NK homeobox gene cluster. Since this region is targeted by the PcG repressor complex which comprises OGT, it is likely that OGT modulates OGA expression at the transcriptional level (Studies have demonstrated that the levels of OGT and OGA would compensate for one another. Upon OGT knockout, inhibition or knockdown, OGA protein levels are reduced . This mial level . Conversal level . Our recal level . Anotheral level . The OGTWhile the OGT and OGA levels are well controlled by intricate transcriptional and posttranscriptional mechanisms, it is likely that such regulation can only exist within a well-tolerated “optimal zone” for a limited period of time. Chronic hypo- or hyper-O-GlcNAcylation would potentially undermine the effectiveness of O-GlcNAc signaling, thus contributing to the pathogenesis of human disease.While the promiscuity of OGT substrate recognition has made it technically challenging to define the specificity of OGT action, it represents a huge ground of opportunities to be exploited. More tools and technologies have to be developed to understand O-GlcNAc signaling. Due to the diversity of substrates that OGT and OGA can act on to regulate cellular function, and the complex compensatory pathways that could take place, delineating the cause and effect remains a major challenge. Future studies are required to investigate the “O-GlcNAc proteomics” with temporal precision and identify potentially the subsets of proteins that are sensitive to different UDP-GlcNAc levels and in different temporal contexts.One understudied component of O-GlcNAc signaling is the spatial contexts of O-GlcNAcylation. In various cellular compartments of the cell, such as the nucleus, mitochondria, cytosol and plasma membrane, OGT and OGA have different physiological roles. Within each cellular region, there are different potential binding partners for both OGT and OGA. Local concentrations of UDP-GlcNAc may also contribute to O-GlcNAcylation of specific substrates Figure . ProfiliA better understanding of the roles of O-GlcNAylation in diverse signaling pathways would be another major direction to be pursued. Development of site-specific O-GlcNAc antibodies would be essential in accelerating our understanding of the function of specific protein O-GlcNAcylation. As O-GlcNAcylation is tightly linked with different PTMs in the cellular metabolic network, it would be useful to identify the intricate relationships among various types of PTMs on proteins. Crosstalk between phosphorylation and O-GlcNAcylation has been relatively well studied, where O-GlcNAcylation can occur reciprocally or sequentially with phosphorylation on the same or different residues. Such studies could be extended to explore the link between O-GlcNAcylation and other PTMs, such as acetylation, methylation, and succinylation and ubiquitination.The cellular signaling machinery is a complex network of components which is only partially understood. The complexity is not only due to the sheer quantity of participants and its high degree of connectivity, but also to the spatiotemporal dimensions of signaling which confers different functions on the same proteins under various contexts. In this review, we have proposed the OGT/OGA pair as a metabolic sensor and an integrator of cellular signaling processes. This relies on the ability of the OGT/OGA complex to receive metabolic and stress signals from multiple upstream partners, and to drive O-GlcNAc modification on diverse sets of downstream targets with precise spatiotemporal control. The OGT/OGA pair is tightly regulated by multiple layers of transcriptional, posttranscriptional and posttranslational control to maintain cellular O-GlcNAc levels within an optimal zone. This “O-GlcNAc meter” ensures O-GlcNAcylation as an effective toolbox to tune and integrate signaling pathways.All authors listed have made a substantial, direct and intellectual contribution to the work, and approved it for publication.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer RT and handling editor declared their shared affiliation at the time of review.


When bias voltage is applied to the MTJ, the TMR ratio of the MnGe-terminated structure suffers a dramatic loss. While the modified MnMn-terminated structure could preserve a large TMR value of 1 × 105%, even bias voltage rises up to 0.1 V, showing a robust bias endurance. These excellent spin transport properties make the CoRhMnGe a promising candidate material for spintronics devices.Equiatomic quaternary Heusler compounds (EQHCs) generally have the advantages of high Curie temperature, large spin polarization and long spin diffusion length, and they are regarded as one of the most promising candidates for spintronics devices. Herein, we report a theoretical investigation on an EQHC CoRhMnGe based magnetic tunnel junction (MTJ) with (i) MnGe-terminated interface and (ii) modified pure Mn terminated interface, i.e., MnMn-terminated interface. By employing first principle calculations combined with non-equilibrium Green's function, the local density of states (LDOS), transmission coefficient, spin-polarized current, tunnel magnetoresistance (TMR) ratio and spin injection efficiency (SIE) as a function of bias voltage are studied. It reveals that when the MTJ under equilibrium state, TMR ratio of MnGe-terminated structure is as high as 3,438%. When the MTJ is modified to MnMn-terminated interface, TMR ratio at equilibrium is enhanced to 2 × 10 Our results show that CoRhMnGe/MgO/CoRhMnGe MTJ possess extremely large TMR value, and such value could be further enhanced when the interface of the MTJ is modified to Mn-rich termination.−6 eV and mesh of 9 × 9 × 1 Monkhorst-Pack k-points in Brillouin zone are applied, and the cut-off energy is set as 500 eV. The optimized distance between the CoRhMnGe layer with MnGe-terminated interface and MgO layer is found to be 2.42 Å, while that between the CoRhMnGe layer with MnMn-terminated interface and MgO layer is found to be 2.02 Å. The spin-dependent transport properties calculations are based on a state-of-the-art technique where DFT is combined with the Keldysh non-equilibrium Green's function (NEGF) theory, as implemented in Nanodcal package  can be calculated by L and ΓR are the coupling matrix of the left electrode and right electrode, respectively; and GR and GA are the retarded and advanced Green's function of the central region, respectively. The transmission coefficient vs. electron energy for MnGe-terminated and MnMn-terminated structures at equilibrium are calculated and displayed in In Physically, tunnel magenetoresistance ratio (TMR) indicates the sensitivity of a MTJ device with respect to the magnetic configuration, and is regarded as one of the most important parameters to characterize performance of a MTJ device. The TMR ratio at zero bias in our work is calculated by the following definition:TPC(Ef) and TAPC(Ef) denote total transmission coefficients at Fermi level in PC and APC, and they are obtained by summing up the contributions of the spin up and spin down channel, thus Tpc(Ef), TAPC(Ef)) is the smaller one of TPC(Ef) and TAPC(Ef). For MnGe-terminated structures, the calculated 5%. It indicates that TMR ratio of CoRhMnGe/MgO/CoRhMnGe MTJ at equilibrium can be greatly enhanced by modifying the interface to MnMn-termination.where k//-resolved transmission in 2-D BZ at Fermi level is also calculated. k//dependence of the spin up and spin down transmission coefficient at E = Ef in PC and APC. (i) In APC, due to the reason we have mentioned above in the transmission curve discussion, the contour plot of transmission coefficient in spin up channel is exactly the same as that in spin down channel, and there is only one transmission contour plot in APC . As shown in The excellent transport properties in MnMn-terminated structures could be intuitively understood by analyzing the local density of states (LDOS). The LDOS of the MnGe-terminated structure and MnMn-terminated structure at equilibrium state are calculated and summed along the transport direction (Iup) and spin down current (Idown), respectively. Here, Itot = Iup + Idown. (i) In PC, spin up current increases linearly with bias voltage up to 0.1 V whilst spin down current always remains minor value and is unresponsive to the increase of bias voltage. Besides, the total currents of these two structures also linearly increase with the increase of bias. (ii) In APC, spin up, spin down and total currents of MnMn-terminated structure always hold minor values when bias ranges from 0 to 0.1 V, indicating that the spin polarized currents of MnMn-terminated structures are significantly inhibited in APC. For MnGe-terminated structures, spin up and spin down currents almost keep the minor values unchanged when bias increases from 0 to 0.09 V, while when bias exceeds the 0.09 V and increases to 0.1 V, spin down current rapidly increases to a very high value of 2.6 nA  is an important parameter that can reveal the degree of the spin polarization in the transport current, and it can be expressed as TMRmax−TMRmin)/TMRmax) exceeds 80%, where TMRmax (or TMRmin) is the maximal  TMR ratio within the range of bias voltage variation. However, the maximal TMR ratio of MnMn-terminated structure reaches up to about 2 × 105%, and it maintains such large value when bias ranges from 0 to 0.06 V. More importantly, when bias increases to 0.06 V, the TMR ratio loss rate of MnMn-terminated structure is only about 6%, and its TMR ratio is still higher than 1 × 105% even for bias up to 0.1 V. It indicates that TMR ratio under bias voltage is greatly enhanced by modifying the interface of CoRhMnGe/MgO/CoRhMnGe MTJ to MnMn-termination, and TMR ratio of such modified structure is much less affected by the bias voltage, showing a robust bias endurance. Besides, in order to characterize the magnitude of the output signal modulation , transmission coefficient, spin-polarized current, tunnel magnetoresistance (TMR) ratio and spin injection efficiency (SIE) as a function of bias voltage are studied. Our calculation reveals that when CoRhMnGe/MgO/CoRhMnGe MTJ under equilibrium state, the TMR ratio of MnGe-terminated structure is as high as 3,438%, while that of modified MnMn-terminated interface can reach up to 2 × 10The raw data supporting the conclusions of this manuscript will be made available by the authors, without undue reservation, to any qualified researcher.All authors listed have made a substantial, direct and intellectual contribution to the work, and approved it for publication.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Fertility preservation in trans women is a crucial but thus far neglected component in the gender confirming treatment in Germany. It is difficult for trans women to access reproductive health care because centers offering treatment, psychological guidance, gender confirming surgery, as well as reproductive health services are scarce in Germany. Legal, social, or financial issues as well as individual patient comorbidities prevent trans women from receiving appropriate counselling. This review provides an overview on options of fertility preservation in trans women. We consider recent publications on testicular regression at the time of gender confirming surgery demonstrating presence of sperm or at least spermatogonia in the majority of tissues. This may open options for cryopreservation of sperm or testicular stem cells in trans women even at the final stage of transition. Hence, standardized urological procedures  and experimental approaches (cryopreservation of testicular tissue with undifferentiated spermatogonia) can be offered best at the initiation but also during the gender confirming process. However, counselling early in the gender confirming process increases the chances of fertility preservation because gender confirming hormone therapy has an impact on spermatogenesis. Fertility preservation is offered to patients at risk of becoming infertile . The horWhile clinical guidelines request the clinician to inform the transgender patient about fertility options, transgender patients themselves often ask for treatment advice. The majority of transgender expressed interest to learn about fertility preservation during the gender confirming process . ReportsDo individuals undergoing gender confirming hormone therapy (GCHT) still have options for fertility preservation? GCHT in trans women consists of treatment with anti-androgens (cyproterone acetate) or spironolactone or gonadotropin releasing hormone agonists in combination with estrogens . This leads to down-regulation of gonadotropin releasing hormone, followed by a prominent decline of luteinizing hormone (LH) and follicle stimulating hormone (FSH). This leads to testicular regression associated with low levels of serum androgens and suppression of spermatogenesis. After several weeks GCHT interrupts germ cell differentiation at the pre-meiotic stage ,21,22. BA total of 90% of transgender persons stated that fertility loss was not relevant to defer the decision to engage in gender affirming medical interventions. . Many trAs yet, no transgender clinic in Germany combines all specialists in one center. This may be desirable due to the significant number of patients with an incidence of 6.8 trans women in 100,000 people worldwide . SeveralThe human testis consists of the interstitium and the tubular compartment (seminiferous tubules). In the interstitium Leydig cells produce testosterone (steroidogenesis). This compartment is also populated by immune and neural cells as well as blood and lymphatic vessels. The tubular compartment consists of peritubular cells, Sertoli cells and germ cells. SSCs are located at the basement membrane of the seminiferous tubules and are capable of undergoing self-renewal as well as differentiating cell divisions. When spermatogonia begin to differentiate they form clones by mitotic divisions. They then enter into meiosis to become spermatocytes. After the two meiotic divisions they populate the seminiferous epithelium as spermatids. After spermiogenesis they are released into the lumen as immotile spermatozoa. Steroidogenesis and spermatogenesis are not only located in separate compartments, they are also controlled by different partly interrogating hormonal axes  . As mentAs published in 2015, we collected in a multi-center setting questionnaires, testicular tissues, and blood serum to evaluate the level of spermatogenesis and steroidogenesis of each trans woman on the day of gender confirming surgery (GCS) [There were 13 publications that reported histological findings of testicular tissues of trans women . The resWe confirmed a highly heterogeneous histological appearance after examining testicular tissues from 108 patients in 2015. Among the patients, 24% had complete spermatogenesis on the day of GCS . In the In general, spermatogenesis is suppressed during GCHT, but complete spermatogenesis or tubules with sperm or spermatozoa are still present in tissues even on the day of GCS, which could help the reproductive clinician to offer different fertility options at different stages of the gender confirming process. Mean testicular weight was 11.35 g in our study group. Individually low testicular weight was associated with impaired spermatogenesis and low serum testosterone . Hence, Before being able to offer suitable options for fertility preservation , it is iEvery trans woman should be counselled about options of fertility preservation. For those trans women who want to preserve their fertility following extensive counselling, different standardized andrological/urological procedures including ejaculate examination, cryopreservation of sperm from the ejaculate, microsurgical testicular sperm extraction (mTESE), or microsurgical epididymal sperm aspiration (MESA) can be offered during the gender confirming process in order to preserve their fertility . Small t®) as well as in other European centers [Cryopreservation of immature testicular tissues containing spermatogonia as most differentiated germ cell type is already offered to pre-pubertal and early pubertal patients prior to initiation of spermatogenesis and at risk of germ cell loss  in Germany  after the diagnosis and before starting GCHT, cryopreservation of sperm after masturbation can be offered. If masturbation is emotionally challenging  or the pIf patients have already started GCHT, but blood values, testicular size, ultrasound, and ejaculate examinations still suggest the presence of intact spermatogenesis, cryopreservation of ejaculated sperm could be offered after masturbation. In azoospermic patients or emotionally challenged patients, mTESE/MESA or experimental methods of extracting and cryopreserving testis tissue only containing spermatogonia can be discussed.If clinicians fail to discuss fertility preservation with the patients or if patients are emotionally challenged by masturbation or financially challenged by an extra procedure/operation during the gender confirming process, (m)TESE methods could still be performed on the day of GCS, looking for spermatozoa during or after the removal of testes. Furthermore, cryopreservation of testicular tissues containing spermatogonia could be offered on the day of GCS in centers where protocols are established and ethical approval is granted for clinical studies.It was shown that up to 80% of transgender persons do have sexual relationships during the gender confirming process and after GCS . If tranOur Centre of Reproductive Medicine and Andrology includes a Department of Clinical and Surgical Andrology. Fertility counselling and fertility preservation are among the services offered to male patients in the clinic. Between December 2012 and February 2019, 16 trans women were counselled for fertility preservation options. Five of these patients (aged between 13 and 62 years) successfully cryopreserved semen specimens with terato- and normozoospermia. In addition to that, two individuals (22 and 33 years) underwent TESE due to azoospermia. To date, none of the individuals who have cryopreserved semen have used these samples in the frame of an assisted reproductive treatment.This review provides and overview regarding the fertility preservation options for trans women. It is of note, however, that trans men and non-binary people may have different needs, which are not addressed in this review. It is advised to discuss fertility options as early as possible during the gender confirming process with trans women in Germany. At this stage of treatment, trans women have intact testes with complete spermatogenesis. During and after GCHT, trans women have disturbed or absent spermatogenesis due to the negative central effect of the hormonal regimens on spermatogenesis. Counselling early increases the chances to retrieve sperm and therefore offers cheap and less-invasive methods for fertility preservation.National and international guidelines demand to counsel trans women about fertility options as early as possible. However, for many reasons, only a minority of trans women undertake efforts to preserve their fertility. To conclude, we strongly advise to counsel trans women regarding fertility preservation options and discuss individual options as early as possible in the gender confirming process in order to fulfill the individual reproductive wish to have one’s own biological children.


HTLV-1/2 are transmitted sexually, by whole cell blood products and from mother-to-child (MTC), mainly through breastfeeding. HTLV-1/2 prevalence in pregnant women is high in Rio de Janeiro, however there were no local studies addressing the rate of adverse pregnancy outcomes (APO) and MTC transmission. The aim was to study sociodemographic characteristics which may be associated to HTLV-1/2 infection and describe pregnancy outcomes and MTC transmission in HTLV-1/2-positive women. The cross-sectional study screened 1,628 pregnant women in of Rio de Janeiro (2012–2014) and found 12 asymptomatic carrier mothers . Pregnancy outcome information was retrieved from medical records. Sociodemographic characteristics were similar between the positive and negative groups except for maternal age, which was higher in carrier mothers. The incidence of adverse pregnancy outcomes was similar in infected and non-infected patients (p = 0.33), however there was a high rate of premature rupture of membranes (PROM) amid infected mothers (3/12). Multilevel logistic regression found that for each additional year of age, the chance of being HTLV-1/2-positive increased 11% and that having another sexually transmitted infection (STI) increased 9 times the chance of being infected. Carrier mothers had more antenatal visits (OR = 5.26). Among the children of HTLV-1/2-positive mothers there was one fetal death, one infant death and one loss of follow-up. After two years of follow-up there was one case of MTC transmission (1/9). The mother reported breastfeeding for one month only. Knowledge about factors associated to HTLV-1/2 infection, its impact on pregnancy outcomes and the MTC transmission rate is important to guide public health policies on antenatal screening and management. HTLV-1/2 are retroviruses transmitted by sex, blood products and from mother to child (MTC), mainly through breastfeeding. There is currently no vaccine, treatment or cure. Although it’s mostly asymptomatic it can cause disabling and even lethal diseases in carriers. The prevalence of HTLV-1/2 in pregnant women at the metropolitan area of Rio de Janeiro is high (0.74%). Our aim was to study the sociodemographic characteristics which may be associated to HTLV-1/2 infection and describe pregnancy outcomes and MTC transmission in the infected population. Apart from being slightly older, there were no differences in the carrier mothers’ sociodemographic profile. Pregnant women with sexually transmitted infections had a 9-fold chance of being HTLV-1/2 positive. Although adverse pregnancy outcomes were not increased, infected mothers had a high rate of ruptured membranes. Among the children of HTLV-1/2-positive mothers there was one fetal death, one infant death and one loss of follow-up. There was one case of MTC transmission (1/9), after one month of breastfeeding. Knowledge about factors associated to HTLV-1/2 infection, its impact on pregnancy, and the MTC transmission rate is important to guide further research and public health policies. Human T-lymphotropic virus types 1 and 2 (HTLV-1/2) are human oncogenic retroviruses first identified in the early 1980’s .HTLV-1/2 viruses are globally distributed and there may be up to 10 million infected worldwide . PrevaleBrazil may be the country with the highest absolute number of HTLV-1/2 carriers in the world. Estimates range from 800,000 to 2.5 million people . Such vaInfection is perennial and most of the patients are asymptomatic reservoirs, sustaining the chain of transmission. In contrast, up to 8% of HTLV-1 carriers develop severe diseases, mainly the highly aggressive adult T-cell leukaemia/lymphoma (ATLL) and the painful and disabling HTLV-1-associated myelopathy/Tropical Spastic Paraparesis. Type 1 virus also causes a spectrum of inflammatory conditions, such as dermatitis and uveitis . In turnLiterature about the effect of HTLV-1/2 infection on pregnancy outcomes is scarce. Only one study on the subject was published. It was conducted in Africa, between 1986 and 1988, involving 45 HTLV-1/2 positive pregnant women and 90 negative ones. No statistically significant differences were found between the groups regarding neither sociodemographic profile, pregnancy and neonatal outcomes .Only four Brazilian researches on HTLV-1/2 in pregnant women and puerperae assessed previous obstetric history and pregnancy outcome, and they reported only on miscarriage –15. Largviscera and from mother-to-child (MTC). The relative importance of each mode of transmission is still largely unknown and most likely it varies with the population involved. In endemic areas such as Japan MTC transmission has been described as the main source of transmission, mainly through breastfeeding [HTLV-1/2 is transmitted via whole cell containing body fluids, mainly through sexual contact, exposure to blood products or tfeeding ,16. Onlytfeeding . In facttfeeding . This retfeeding . Higher tfeeding ,20–22. Otfeeding ,23.The aim of the research was to describe the epidemiological profile of pregnant women diagnosed with HTLV-1/2 in the metropolitan area of Rio de Janeiro, the occurrence of adverse pregnancy outcomes (APO) and the rate of mother-to-child transmission.The study population consisted of 1,628 pregnant women. The first 1,204 were enrolled at admission for delivery as part of a research on HTLV-1/2 prevalence conducted at two public hospitals in the metropolitan area of Rio de Janeiro: the ‘Pedro Ernesto’ University Hospital of the Rio de Janeiro State University (Universidade do Estado do Rio de Janeiro–HUPE/UERJ) and the ‘Hospital Estadual da Mãe’ (HEM). HUPE is a referral centre for high-risk patients while HEM, situated at the adjacent city of Mesquita, assists low and medium-complexity cases . As a reBlood for HTLV-1/2 screening was collected either during the routine antenatal care or at the admission for delivery by chemiluminescent microparticle immunoassay . Children’s samples were also screened by CMIA within the month after birth, at six months, one and two years of age. Infection was confirmed if the child remained seropositive after 24 months, and additional yearly exams were performed for follow-up. Reactive samples were confirmed by Western blot . Two pregnant women with positive screening tests and negative WB results were considered false positive and allocated to the negative group in the statistical analysis. Routine antenatal screening for sexually transmitted infections (STI) in Brazil consists of VDRL test for syphilis and ELISA tests for HIV, hepatitis B and C. In case of positive screening the confirmation tests are FTA-Abs for syphilis and western blot for HIV. All tests were done at HUPE/UERJ’s Clinical Analysis Laboratory.This research complies with the Declaration of Helsinki and the Resolution 466 of December 12, 2012 of the Brazilian Ministry of Health. The project was approved by the Rio de Janeiro State University Research and Ethics Committee  and sponsored by the Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro . Written informed consent was obtained from all the subjects and from the legally authorized representatives of the minors who agreed to take part in the research. Anonymity and data confidentiality were guaranteed.Means, medians, standard deviations and percentages were used to describe the results. Medians were used to define the cutoff point used to convert numerical variables to categorical ones . The following variables were considered as adverse pregnancy outcomes: fetal demise, perinatal death, maternal hypertensive syndrome, preterm birth and admission to the neonatal intensive care unit. A composite variable named ‘adverse outcome’ was created in view of the low frequency of each adverse obstetric outcome studied. Missing data were excluded from the statistical analyses. Mann-Whitney and Fisher’s exact tests were used to compare categorical variables between the HTLV-1/2 positive (G1) and negative (G2) groups. Multilevel logistic regression was performed to assess the factors associated to HTLV-1/2 infection. Age, number of pregnancies, coinfection with other STI, condom use in pregnancy and number of antenatal appointments were included in the model as fixed effects and "Hospital" was included as random effects (random intercept). The Epi-info software version 3.5.2 and the R-Project version 3.3.1 were used for building the database and performing the statistical analyses.Prevalence of HTLV-1/2 infection in this study population was 0.74% (12/1628), with no significant difference between the hospitals .Among the sociodemographic characteristics  only matSexual and reproductive characteristics are summarized in The prevalence of comorbidities was high in the study population (37.6%), being significantly more frequent in HUPE (78.1%) than in HEM . However, the rate was similar between the infected and non-infected groups (p = 0.16).There were five adverse pregnancy outcomes in the HTLV positive group. The difference was not significant when compared to the negative group (p = 0.33) . There wDifferences in maternal age, STI coinfection and the number of antenatal visits remained significant after multivariate logistic regression .Multilevel Logistic regression model–dependent variable: HLTV; fixed effects: age, number of pregnancies, coinfection with other STI, condom use in pregnancy, number of antenatal appointments; random effects: hospital.Each additional year of maternal age increased the chance of being HTLV-1/2 positive in 11% (OR = 1.11). Having another STI increased 9 times the chance of being infected (OR = 9.27). In G1 there was a higher frequency of antenatal visits (OR = 5.31) .Among the children of the 12 HTLV-1/2 infected mothers, there was one fetal demise, one infant death and one loss of follow-up. The fetal death occurred at 24 weeks of pregnancy and the infant died at two months of age due to pneumonia. One child had its seroconversion (1/9) confirmed after two years of age. She was born at January 2013 and remains asymptomatic under medical surveillance at the HUPE to date. Her mother referred breastfeeding for less than one month. The other eight children were periodically monitored, seven at the pediatric infectology department of UERJ and one at its local health care center. Despite their economic difficulty, their mothers reported avoiding breastfeeding since they were aware of their carrier status.The HTLV-1/2 prevalence found was consistent with the study previously published by our group which recruited only women admitted for delivery .The sociodemographic profile of both groups was similar except for the older age found in the infected group. This is in accordance with the international literature on the disease’s epidemiology  and withcirca 21%) among HTLV-1/2-positive and negative patients (p = 0.86). This was in accordance with data from other endemic areas [Regarding the reproductive history, it’s striking that almost half of the carrier mothers 5/12) had previous adverse obstetric outcomes . Three of these women had no comorbidities. It must be said however, that no causal link to HTLV-1/2 can be inferred since their infectious status was unknown during the previous pregnancies. The prevalence of early miscarriages was similar . In a recent Brazilian study using data from the Ministry of Health , PROM waIn our study, the mother of the only infected child reported breastfeeding for less than one month. Mother-to-child transmission of HTLV-1/2 occurs mainly through breastfeeding, ranging from 3.9% to 22% in endemic areas . The polOn the other hand, a strength of the study is that the children of infected mothers were followed up for three years, a gold standard set by the Nagazaki study group . This waThe study confirmed the high prevalence of HTLV-1/2 in pregnant women at the metropolitan area of Rio de Janeiro and found no sociodemographic difference between infected and non-infected patients. Carrier mothers frequently reported previous adverse pregnancy outcomes (5/12), but at the current pregnancy there was only one unexplained fetal demise (growth restricted) and one admission to the NICU due to sepsis. There was a significant association to other STI, but the intriguing point was the number of PROM cases among infected women (3/12).Since there is no treatment or immunization for HTLV-1/2, preventive measures are currently the only effective way to break the chain of transmission. Thus, it is vital to increase awareness about the infection among health providers and the population. Safe sex campaigns are already extensive, therefore tackling MTC transmission is likely to have the most significant effect on the longitudinal perpetuation of the virus and the reduction of HTLV-1/2 associated diseases, particularly in endemic areas. There are no studies on antiretroviral therapy or mode of delivery to address the potential for reducing MTC transmission. Thus, avoidance of breastfeeding remains the only effective way to block the MTC transmission of the virus. The use of this strategy as a public policy in low income areas is still not a consensus, since breastfeeding also plays a role in reducing infant mortality and morbidity through immunity boosting and protecting against infections.Since there is no clear difference in the sociodemographic profile of HTLV-1/2 carriers, routine prenatal screening at endemic areas is supported by several research groups ,31,40–42Further studies are needed on the cost-effectiveness of such strategy across different prevalence areas and socioeconomic resources. Moreover, epidemiological mapping of prevalence and mother-to-child transmission is needed to guide public health policies on antenatal screening and management. Additionally, better understanding of the burden of the infection in pregnancy may help to improve HTLV-1/2 infected mothers’ antenatal care and their children’s outcome.S1 DatabasePatients database.(XLS)Click here for additional data file.


Myxococcus xanthus and is thus named NmpR, NtrC Modulator of Pili Regulator. A complex multi-component signaling system including NmpR was revealed by suppressor mutations that restored motility to cells lacking PilR, an evolutionarily conserved RR required for expression of pilA encoding the major Type-IV pilus monomer found in many bacterial species. The system contains at least four signaling proteins: a SK with a protoglobin sensor domain (NmpU), a hybrid SK (NmpS), a phospho-sink protein (NmpT), and an NtrC-like RR (NmpR). We demonstrate that ΔpilR bypass suppressor mutations affect regulation of the NmpRSTU multi-component system, such that NmpR activation is capable of restoring expression of pilA in the absence of PilR. Our findings indicate that pilus gene expression in M. xanthus is regulated by an extended network of TCS which interact to refine control of pilus function.Two-component signaling systems (TCS) regulate bacterial responses to environmental signals through the process of protein phosphorylation. Specifically, sensor histidine kinases (SK) recognize signals and propagate the response via phosphorylation of a cognate response regulator (RR) that functions to initiate transcription of specific genes. Signaling within a single TCS is remarkably specific and cross-talk between TCS is limited. However, regulation of the flow of information through complex signaling networks that include closely related TCS remains largely unknown. Additionally, many bacteria utilize multi-component signaling networks which provide additional genetic and biochemical interactions that must be regulated for signaling fidelity, input and output specificity, and phosphorylation kinetics. Here we describe the characterization of an NtrC-like RR that participates in regulation of Type-IV pilus-dependent motility of  Myxococcus xanthus signaling system of previously unknown function restore Type-IV pilus-dependent motility to cells lacking PilR, a response regulator typically required for production of the pilin monomer PilA. Suppressor mutations in ΔpilR cells led to activation of a related signaling system, resulting in expression of pilA and the corresponding production of PilA to restore motility. Thus, both PilSR and NmpSR coordinately regulate motility in M. xanthus. Collectively, our results expand our understanding of the activation of response regulators via phosphorylation and the mechanisms controlling multi-component signal transduction systems.Sensing and responding to the environment are critical for bacterial survival and adaptation. Many bacteria sense environmental signals through biological machinery referred to as two-component signaling systems. These signaling systems are composed of a sensor histidine kinase and a cognate response regulator and serve to regulate gene expression in response to environmental cues. Due to their importance for survival, many bacterial genomes encode multiple two-component systems, some of which arose from gene duplication events. However, the mechanisms by which two-component systems integrate multiple inputs within larger networks remains poorly defined. In this study, we demonstrate that suppressor mutations within a  Two-component signaling systems (TCS) regulate numerous bacterial responses to environmental signals. These biological machines typically contain a membrane associated sensor histidine kinase (SK) and a cognate cytoplasmic response regulator (RR) that function together to propagate a response that is facilitated by the phosphorylation and dephosphorylation of the RR by the dual-function SK . FollowiEscherichia coli and Salmonella typhimurium . An. AnAnaer lineage . Moreovend fungi –72. Theyalinarum . Thus, w pathway . It is w targets . In natuA. dehalogenans Fw109-5 mentioned above preferentially transfers the phosphoryl group to the first receiver domain of the NmpT homologue ATP). Aliquots were removed at various time points and stopped by the addition of an equal volume of 4x SDS loading buffer. Samples were resolved by electrophoresis on 12% SDS-polyacrylamide gels. Gels were exposed for 3 hours to a phosphor screen and visualized using a Typhoon Imager (GE). For phosphotransfer profiling, kinases were allowed to autophosphorylate for two hours until maximal phosphorylation levels were reached. A 5 μl aliquot of the phosphorylated SK was mixed with 5 μl of 10 μM RR, and reactions were stopped at various times by addition of 4x SDS loading buffer. Incorporation of labeled phosphoryl groups was analyzed as detailed above and figure images are representative of multiple experiments.Kinase assays were performed as described previously . Briefly4)2SO4, 1 mM DTT, Tween 20 0.2%, and 30 mM KCl. Reaction conditions were determined empirically in our laboratory but were based on recommendations from the DIG Gel Shift Kit (Sigma-Aldrich). NmpR was incubated with the DNA probes for 15 minutes at room temperature and then loaded on 8% acrylamide non-denaturing PAGE gels . Gels were resolved at 60 v for ~2 hours, then stained with ethidium bromide (10 μg per 10 ml H2O) for 15 minutes prior to visualization. Presented images are representative of reproducible independent reactions.Full-length wild-type NmpR was expressed, purified, and quantified as above. DNA probes were generated by PCR with Failsafe polymerase with Buffer K , purified with Qiagen QIAquick PCR Purification Kit, and quantified by spectrophotometry. Probes were diluted in 10 mM Tris-HCl, pH8.5 to 100 fmol/μl with a final quantity of 200 fmol used per individual binding reaction. Probes were incubated with increasing concentrations of NmpR, as indicated, in a reaction containing a final concentration of 20 mM Hepes pH 7.6, 1 mM EDTA, 10 mM (NHblast.ncbi.nlm.nih.gov) against δ-proteobacteria (taxid:28221) specifically, or by excluding δ-proteobacteria. Homologues and synteny were also identified at Pfam  [Several online software platforms were utilized to identify homologues of NmpRSTU. Protein sequences and some synteny analysis were obtained from the Mist 2.2 database . Homologfam.org; ) and Synfam.org; ). The stasy.org) .S1 Table(DOCX)Click here for additional data file.S2 Table(DOCX)Click here for additional data file.S1 FiggroES promoter was reasonable to use for complementation experiments, a groES-lacZ reporter was constructed and transformed into relevant strains used in this research. The Miller Units reported in this Figure are directly comparable to the levels of the pilA reporter: ((OD420/mg protein * time in minutes)*1000). The levels of groES expression are essentially identical between the strains tested here, when assayed following growth on a hard agar surface.To determine if the (TIFF)Click here for additional data file.S2 FigSome members of the ∂-proteobacteria contain homologues of the multi-component signaling pathway  (A). Mxan_4236 (purple) is a CBS domain protein and serves as a convenient landmark of the genomic location (A). Only a NmpU homologue could be identified in more distantly related ∂-proteobacteria (B). Shared synteny was also identified outside of the ∂-proteobacteria (C) and multiple examples of NmpU/NmpT homologues (D) were identified outside of the ∂-proteobacteria. Those species identified with a * are all members of the Planctomycetes phylum. Collectively, these observations suggest these genes have been exchanged by horizontal gene transfer followed by divergent evolution of domain architectures.(TIFF)Click here for additional data file.


Myelin sheaths on vertebrate axons provide protection, vital support and increase the speed of neuronal signals. Myelin degeneration can be caused by viral, autoimmune or genetic diseases. Remyelination is a natural process that restores the myelin sheath and, consequently, neuronal function after a demyelination event, preventing neurodegeneration and thereby neuron functional loss. Pharmacological approaches to remyelination represent a promising new frontier in the therapy of human demyelination pathologies and might provide novel tools to improve adaptive myelination in aged individuals. Recent phenotypical screens have identified agonists of the atypical G protein-coupled receptor Smoothened and inhibitors of the glioma-associated oncogene 1 as being amongst the most potent stimulators of oligodendrocyte precursor cell (OPC) differentiation in vitro and remyelination in the central nervous system (CNS) of mice. Here, we discuss the current state-of-the-art of studies on the role of Sonic Hedgehog reactivation during remyelination, referring readers to other reviews for the role of Hedgehog signaling in cancer and stem cell maintenance. The Hedgehog (Hh) signaling pathway is an evolutionary conserved signal transduction pathway that plays a crucial role during embryonic development and tissue regeneration in vertebrates. Hh ligands, namely Sonic Hedgehog (Shh), Desert Hedgehog (Dhh) and Indian Hedgehog (Ihh), have similar binding affinities for membrane receptors called Patched (PTCH). Shh acts to establish cell fate in the developing limb, somites and the neuronal tube, Ihh is involved in chondrocyte development and Dhh in germ cell development. In the canonical Hh signaling pathway, the interaction of an Hh ligand with PTCH receptors activates the orphan G protein-coupled seven-pass transmembrane receptor Smoothened (Smo) in a chain of events that culminates in a change of balance between activator and repressor forms of the glioma-associated oncogenes Gli1-3). In the absence of the Hh ligand, the Gli transcription factors are bound to Suppressor of Fused (SUFU). Upon Smo activation, the Gli proteins migrate to the nucleus where they regulate Hh-dependent gene transcription -3. In th,3. The SNeurons depend on oligodendrocytes (OLs) for the release and re-uptake of neurotransmitters, neurotropic factors and metabolites but also for axon guidance and protection from oxidative stresses, just to name some of the many functions of glia/neuron association . Thus, iHere, we review the main aspects of Shh signaling reactivation during remyelination and how Smo agonists promote OPC differentiation, taking into consideration recent structural and mechanistic studies on the mechanism of Smo activation.The process of CNS myelination begins during embryogenesis and is completed during adolescence. Secreted Shh is required during embryogenesis for the early appearance of OPCs in the spinal cord and forebrain and favours the maturation of OL neurospheres derived from embryonic rat brain . Shh mouIn humans, myelin remains in place for life unless environmental or metabolic stress(es) or genetic dysfunction(s) damage its integrity ,28,29. A+) cells are recruited to areas of demyelination from the Sub Ventricular Zone (SVZ) following Shh signaling reactivation, and from there, migrate into the corpus callosum [Shh morphogenetic signaling is not active in most CNS adult tissues but it is reactivated during remyelination ,34. Studcallosum ,36,37. Scallosum , the aducallosum , and in callosum .Single-cell RNA sequencing of OPC subtypes obtained from OPCs derived from 10 different regions of mouse juvenile and adult CNS has shown that diverse subtypes of mature OLs are present in different CNS regions, although some populations are present in all regions. This high-resolution view of the transcriptional landscape of OPC maturation in the murine CNS showed that there are at least six distinct OL transcriptional phases, despite the fact that OPC maturation to OLs is a transcriptional continuum that can occur at different times of life in different brain regions  Figure .+/Olig2+ cells-expressing Ki67, a marker of proliferating cells [Shh upregulation is observed in NSCs of the OL lineage involved in lesion repair but not in normal adult white matter . The Shhng cells . Deletiong cells .During remyelination, Shh signaling works in concert with epidermal growth factors (EGFs) and fibroblast growth factors (FGFs) that are among the major soluble factors regulating NSC re-entry into the cell cycle and the migration of neuroblasts ,49. Smo Remyelination studies performed with LPC-induced focal demyelination animal models have indicated that the expression and transcriptional activation of several downstream components of Shh signaling is required for NSC differentiation to OPCs. PTCH, Smo, Gli1 and Gli2 are expressed in the area of the brain lesion at early stages of remyelination while Gli3 is not. Conditional inactivation of PTCH (Ptc) in mice enabled a study of the function of Shh signaling in the absence of a ligand in the SVZ. Interestingly, Ptc mutants showed an increase in EGFR expression, again supporting the view that Shh and EGFR signaling are co-regulated during remyelination ,35.CE/+, SmoFxFx; RCE mice) does not increase the amount of NSCs or alter their cell fate, indicating that Gli1 downregulation upon Smo activation represents a specific signal that constrains NSC proliferation at remyelinating lesions. Unexpectedly, Smo activation in the absence of Gli1 function has even greater effects on NSC proliferation and increases NSC mobilization [Gli1 is considered as the canonical downstream effector of Shh/Smo signaling . Gli1 islization . Previoulization .The Smo agonist SAG activates Hh signaling through both canonical and non-canonical pathways ,53. MicrIn summary, accumulating data ,54,55,56Much less is understood about the role of Shh/Smo signaling in the passage of OPCs from pre-OLs  to myeliMyRF gene deletion did not alter recruitment or initial differentiation of OPCs in LPC-induced demyelination of the corpus callosum in mice but decreased the density of new glutathione S-transferase π-positive oligodendrocytes and impaired remyelination in the spinal cord and corpus callosum, showing incapacity to express myelin proteins [MyRF gene expression in OLs during development, and MyRF gene expression activates a cascade of events, leading to axon engagement in the healthy CNS. Interestingly, it has been observed that conditional ablation of MyRF in the brain leads to an inability of mice to adapt to environmental changes required for adaptive learning, a process that requires myelination of novel axons [MBP and MAG gene expression in primary OPCs [MBP gene expression and the morphological changes accompanying Oli-neuM differentiation upon Clobetasol treatment require Smo activation and RxRγ gene transcription as cyclopamine or itraconazole treatment reduces MBP expression in Clobetasol-treated Oli-neuM and RxRγ inhibition in Clobetasol-treated Oli-neuM results in MBP downregulateion [RxRγ gene expression is upregulated at remyelination lesions in MS patients and its downregulation in cultured OPCs results in depletion of differentiated OLs in purified OPC cultures, with OLs stalled at the premyelination stage. However, neither the ligand that stimulates its transcription nor its receptor-binding partner has been identified under remyelination stimuli [The potential requirement of Smo activation for the transition of pre-OLs into mature OLs expressing myelin genes is suggested by the finding that two glucocorticoids that act as Smo agonists , Clobetaproteins . Extraceel axons . Supportary OPCs . Clobetaulateion . RxRγ caulateion . RxRγ ge stimuli .The finding that Shh signaling is activated in cancer cells has powered the search for Smo or Gli antagonists ,70,71,72Staurosporinone, zerumbone, arcyriaflavin C, physalin B and physalin F can effectively inhibit both Gli1- and Gli2-mediated transcription. GANT61 has been tested for its therapeutic potential in the EAE model for relapsing remitting MS  by speciThe canonical Shh signal relies on Smo translocation to the tip of the primary cilium to change the balance of Gli transcriptional activators (GliA), primarily Gli2A, and Gli transcriptional repressors GliR, ,79,80). ,80. 79,8Gli1 gene is required for Hh signaling in zebra fish [Gli1 gene [Gli1 gene insertion into the Gli2 locus, while Gli3 cannot [The bra fish  but not bra fish , althougbra fish ,86. Receli1 gene . Gli2 mu3 cannot . The mou3 cannot . Degrada3 cannot . Gli2 is3 cannot .Heterozygous mutations in Gli3 account for several dominant diseases of variable severity, including Greig cephalopolysyndactyly syndrome  ,91, PallThe finding that Gli1 is downregulated in Shh-responsive NSCs suggested that a non-canonical pathway of Gli1 inactivation might be activated in Shh-responsive NSCs originating from the SVZ during remyelination . So far,Gli genes have also been shown to negatively regulate one another and EGFR signaling leads to decreased expression of Hh signaling components, whereas inhibition of Hh signaling leads to increased EGFR signaling [Gli1 gene transcription either by preventing Gli1 protein degradation or by acting on Gli1 phosphorylation. The activation of Hh signaling in pancreatic cancer cells has been reported to be consequent to the block of the proteasome-mediated Gli1 degradation caused by oncogenic Kras. In human keratinocytes, Gli1 and Gli2 are stabilized by preventing their degradation via the proteasome pathway by EGFR-activated ERK1/2 [Gli proteins, mainly Gli1, have been reported to be activated by AKT ,98, MAPKignaling . The KRAd ERK1/2 .The relationship between mTOR/S6K1 signaling and myelination is indicated by the observation that deletion of Raptor, Rheb1 or mTORC1 causes hypomyelination and reduction of OLs and an accumulation of OPCs in the spinal cord ,107,108.AMP-activated Protein Kinase (AMPK) signaling has a protective role for OLs under pathological conditions and delays disease progression in EAE. Interestingly, Metformin, an AMPK activator, attenuates increased inflammation and demyelination in the CNS compartment of the EAE animal model . Gli1 acTGF and its receptors are widely expressed in the human body, and its signaling plays a major role in human diseases including multiple sclerosis. There is increasing evidence to show that TGF signal transduction interacts with the Hh pathway downstream of Smo not only in normal fibroblasts and keratinocytes but also in various cancer cell lines. The TGF-/smad3 cascade results in Gli2 induction via a mechanism independent of the Hh/Ptch/Smo axis and does not require de novo protein synthesis . In pancNotch activity affects the trafficking of Smo and PTCH1 to primary cilia, suggesting its interference in the transmission of Smo signaling . The NotRxRs and LxR gene expression. Thus, there exists a clear relationship among myelination, cholesterol biosynthesis, Clobetasol-mediated MBP expression and Shh signaling activation during OPC differentiation into myelinating OLs, but the molecular players that connect Smo activation to myelination during OPC maturation remain to be identified.Shh ligand formation depends on cholesterol for its biosynthesis, and cholesterol is necessary for the expression of genes that encode myelin proteins since mutations that affect cholesterol biosynthesis cause hypomyelination and reduce levels of myelin gene transcripts . SimilarPTCH1 and PTCH2 genes have likely different functions. Two PTCH receptors bind one Shh ligand [The Shh ligand is a soluble factor that originates from the cholesterol-mediated autocatalytic cleavage of the Shh precursor . In the h ligand .How the Shh signal is transduced from PTCH to Smo remained unclear for a long time. Recent structural studies have clarified that PTCH suppresses the activity of Smo by impairing conformational changes induced by sterol binding ,130. It S)hydroxycholesterol, and CRD mutations that abolish binding to cholesterol impair Smo activation [The crystal structure of cholesterol-bound Smo has been recently reported . These stivation ,137. Thitivation ). The cotivation .The fact that Shh processing and ligand formation requires cholesterol as well as the fact that Smo activation depends on cholesterol binding suggests that cholesterol abundance and accessibility at OPC membranes might have a regulatory role in NSC proliferation and OPC differentiation from pre-OLs to myelinating OLs. This would represent an additional level or regulation of OPC maturation into myelinating OLs during remyelination processes.SQS gene (Fdft1), an essential enzyme in cholesterol biosynthesis, show severe perturbation of myelin synthesis by OLs and a reduced rate of myelination in white matter, although purified myelin from SQS mutant mice has an almost normal composition of proteins and lipids, including the characteristic high cholesterol level [Indeed, several genetic disorders of the cholesterol biosynthetic pathway are associated with demyelination with or without craniofacial malformations and accumulation of sterol intermediate precursors ,138. OLsol level . Thus, tol level , Smo actol level ,20 and Ool level ,17.How Shh reactivation leads to NSC differentiation toward the OPC lineage during remyelination processes is beginning to be clarified ,43,48,52