E3 ubiquitin-protein ligase whose activity is dependent on E2 enzymes, UBE2D1, UBE2D2, UBE2E1 and UBE2E2 (    , ). Forms a ubiquitin ligase complex in cooperation with the E2 UBE2D2 that is used not only for the ubiquitination of USP4 and IKBKB but also for its self-ubiquitination (, ). Component of cullin-RING-based SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complexes such as SCF(SKP2)-like complexes . A TRIM21-containing SCF(SKP2)-like complex is shown to mediate ubiquitination of CDKN1B ('Thr-187' phosphorylated-form), thereby promoting its degradation by the proteasome . Monoubiquitinates IKBKB that will negatively regulates Tax-induced NF-kappa-B signaling . Negatively regulates IFN-beta production post-pathogen recognition by catalyzing polyubiquitin-mediated degradation of IRF3 . Mediates the ubiquitin-mediated proteasomal degradation of IgG1 heavy chain, which is linked to the VCP-mediated ER-associated degradation (ERAD) pathway . Promotes IRF8 ubiquitination, which enhanced the ability of IRF8 to stimulate cytokine genes transcription in macrophages (By similarity). Plays a role in the regulation of the cell cycle progression . Enhances the decapping activity of DCP2 . Exists as a ribonucleoprotein particle present in all mammalian cells studied and composed of a single polypeptide and one of four small RNA molecules (, ). At least two isoforms are present in nucleated and red blood cells, and tissue specific differences in RO/SSA proteins have been identified . The common feature of these proteins is their ability to bind HY RNAs.2 . Involved in the regulation of innate immunity and the inflammatory response in response to IFNG/IFN-gamma . Organizes autophagic machinery by serving as a platform for the assembly of ULK1, Beclin 1/BECN1 and ATG8 family members and recognizes specific autophagy targets, thus coordinating target recognition with assembly of the autophagic apparatus and initiation of autophagy . Regulates also autophagy through FIP200/RB1CC1 ubiquitination and subsequent decreased protein stability . Represses the innate antiviral response by facilitating the formation of the NMI-IFI35 complex through 'Lys-63'-linked ubiquitination of NMI . During viral infection, promotes cell pyroptosis by mediating 'Lys-6'-linked ubiquitination of ISG12a/IFI27, facilitating its translocation into the mitochondria and subsequent CASP3 activation . When up-regulated through the IFN/JAK/STAT signaling pathway, promotes 'Lys-27'-linked ubiquitination of MAVS, leading to the recruitment of TBK1 and up-regulation of innate immunity . Mediates 'Lys-63'-linked polyubiquitination of G3BP1 in response to heat shock, leading to stress granule disassembly .
Subcellular locations: Cytoplasm, Cytoplasmic vesicle, Autophagosome, Nucleus, Cytoplasm, P-body, Cytoplasm, Stress granule
Enters the nucleus upon exposure to nitric oxide . Localizes to small dot- or rod-like structures in the cytoplasm, called processing bodies (P-bodies) that are located underneath the plasma membrane and also diffusely in the cytoplasm . They are located along the microtubules and are highly motile in cells . Colocalizes with DCP2 in P-bodies . Localizes to stress granules in response to oxidative stress .
Isoform 1 and isoform 2 are expressed in fetal and adult heart and fetal lung.