ATF6B

The protein encoded by this gene is a transcription factor in the unfolded protein response (UPR) pathway during ER stress. Either as a homodimer or as a heterodimer with ATF6-alpha, the encoded protein binds to the ER stress response element, interacting with nuclear transcription factor Y to activate UPR target genes. The protein is normally found in the membrane of the endoplasmic reticulum; however, under ER stress, the N-terminal cytoplasmic domain is cleaved from the rest of the protein and translocates to the nucleus. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2008]

Full Name

Activating Transcription Factor 6 Beta

Function

Cyclic AMP-dependent transcription factor ATF-6 beta: Precursor of the transcription factor form (Processed cyclic AMP-dependent transcription factor ATF-6 beta), which is embedded in the endoplasmic reticulum membrane (PubMed:11256944).
Endoplasmic reticulum stress promotes processing of this form, releasing the transcription factor form that translocates into the nucleus, where it activates transcription of genes involved in the unfolded protein response (UPR) (PubMed:11256944).
Processed cyclic AMP-dependent transcription factor ATF-6 beta: Transcription factor that acts in the unfolded protein response (UPR) pathway by activating UPR target genes induced during ER stress (PubMed:11256944).
Binds DNA on the 5'-CCAC[GA]-3' half of the ER stress response element (ERSE) (5'-CCAATN9CCAC[GA]-3') when NF-Y is bound to ERSE (PubMed:11256944).

Biological Process

ATF6-mediated unfolded protein response Source: ParkinsonsUK-UCL
Endoplasmic reticulum unfolded protein response Source: GO_Central
Negative regulation of ATF6-mediated unfolded protein response Source: UniProtKB
Positive regulation of transcription by RNA polymerase II Source: NTNU_SB
Positive regulation of transcription from RNA polymerase II promoter in response to endoplasmic reticulum stress Source: ParkinsonsUK-UCL
Regulation of transcription by RNA polymerase II Source: GO_Central
Signal transduction Source: ProtInc

Cellular Location

Endoplasmic reticulum membrane
Processed cyclic AMP-dependent transcription factor ATF-6 beta: Nucleus. Under ER stress the cleaved N-terminal cytoplasmic domain translocates into the nucleus.

Topology

Cytoplasmic: 2-396 aa
Helical: 397-417 aa
Lumenal: 418-703 aa

PTM

N-glycosylated.
During unfolded protein response, a fragment of approximately 60 kDa containing the cytoplasmic transcription factor domain is released by proteolysis. The cleavage is probably performed sequentially by site-1 (MBTPS1, S1P) and site-2 (MBTPS2, S2P) proteases.