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. May protect neuroblastoma cells from ER stress-induced death. In vitro activates transcription of target genes via direct binding to the CRE site. 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. 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). Belongs to the bZIP family. ATF subfamily.