Transcription factor involved in unfolded protein response (UPR). In the absence of endoplasmic reticulum (ER) stress, inserted into ER membranes, with N-terminal DNA-binding and transcription activation domains oriented toward the cytosolic face of the membrane. In response to ER stress, 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 to effect transcription of specific target genes. Plays a critical role in chondrogenesis by activating the transcription of SEC23A, which promotes the transport and secretion of cartilage matrix proteins, and possibly that of ER biogenesis-related genes (PubMed:19767744). In a neuroblastoma cell line, protects cells from ER stress-induced death (PubMed:17178827). In vitro activates transcription of target genes via direct binding to the CRE site (PubMed:17178827). Binds DNA as a dimer. 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. Upon ER stress, translocated into the nucleus. Widely expressed, including in lung, bladder, ovary, testis and spleen (PubMed:17178827). Highly expressed in chondrocytes (PubMed:19767744). Up-regulated by ER stress at the transcript and protein levels, the increase at the protein level is much higher than at the transcript level. This induction is accompanied by increased proteolytic cleavage that releases the N-terminal transcription factor domain. Up-regulated in brain areas undergoing ischemic injury, in neurons, but not astrocytes. Up-regulated by SOX9 during chondrocyte differentiation, possibly through SOX9-induced mild ER stress (PubMed:19767744). Upon ER stress, translocated to the Golgi apparatus, where it is processed by regulated intramembrane proteolysis (RIP) to release the cytosol-facing N-terminal transcription factor domain. The cleavage is performed sequentially by site-1 and site-2 proteases (S1P/MBTPS1 and S2P/MBTPS2). N-glycosylated. Ubiquitinated by HRD1/SYVN1; undergoes 'Lys-48'-linked ubiquitination, followed by rapid proteasomal degradation under normal conditions. Upon ER stress, SYVN1 E3 ubiquitin-protein ligase dissociates from its substrate, ubiquitination does not occur and CREB3L2 is stabilized. Mutant mice are born at the expected Mendelian rate, but die by suffocation shortly after birth because of an immature chest cavity. They exhibit severe chondrodysplasia. The cartilage shows a lack of typical columnar structure in the proliferating zone and a decrease in the size of the hypertrophic zone, resulting in a significant reduction of extracellular matrix proteins. Proliferating chondrocytes show abnormally expanded ER, containing aggregated type II collagen and cartilage oligomeric matrix protein (COMP). Displays significant decrease in Sec23a levels. Belongs to the bZIP family. ATF subfamily.