Precursor of the transcription factor form (Processed cyclic AMP-responsive element-binding protein 3-like protein 1), which is embedded in the endoplasmic reticulum membrane with N-terminal DNA-binding and transcription activation domains oriented toward the cytosolic face of the membrane ( ). In response to ER stress or DNA damage, transported to the Golgi, where it is cleaved in a site-specific manner by resident proteases S1P/MBTPS1 and S2P/MBTPS2. The released N-terminal cytosolic domain is translocated to the nucleus where it activates transcription of specific target genes involved in the cell-cycle progression inhibition ( ).
Transcription factor involved in cell type specific DNA damage and unfolded protein response (UPR). Binds the DNA consensus sequence 5'-GTGXGCXGC-3' . Plays a critical role in bone formation through the transcription of COL1A1, and possibly COL1A2, and the secretion of bone matrix proteins. Directly binds to the UPR element (UPRE)-like sequence in an osteoblast-specific COL1A1 promoter region and induces its transcription. Does not regulate COL1A1 in other tissues, such as skin (By similarity). Required to protect astrocytes from ER stress-induced cell death. In astrocytes, binds to the cAMP response element (CRE) of the BiP/HSPA5 promoter and participate in its transcriptional activation (By similarity). In astrocytes and osteoblasts, upon DNA damage, inhibits cell-cycle progression after G2/M phase by binding to promoters and activating transcription of genes encoding cell-cycle inhibitors, such as p21/CDKN1A (By similarity). Required for TGFB1 to activate genes involved in the assembly of collagen extracellular matrix .
(Microbial infection) May play a role in limiting virus spread by inhibiting proliferation of virus-infected cells. Upon infection with diverse DNA and RNA viruses, inhibits cell-cycle progression by binding to promoters and activating transcription of genes encoding cell-cycle inhibitors, such as p21/CDKN1A .
Subcellular locations: Endoplasmic reticulum membrane
ER membrane resident protein. Upon ER stress, translocated to the Golgi apparatus where it is cleaved. The cytosolic N-terminal fragment (processed cyclic AMP-responsive element-binding protein 3-like protein 1) is transported into the nucleus.
Subcellular locations: Nucleus
Upon ER stress or DNA damage, transported into the nucleus.
Expressed in several tissues, with highest levels in pancreas and prostate. Expressed at relatively lower levels in brain.