Like its homolog ATF6 (reviewed in Fox and Andrew 2015), ATF...

created [InstanceEdit:8874818] May, Bruce, 2016-05-29
dbId 8874819
displayName Like its homolog ATF6 (reviewed in Fox and Andrew 2015), ATF...
modified [InstanceEdit:9965892] May, Bruce, 2025-09-07
schemaClass Summation
text Like its homolog ATF6 (reviewed in Fox and Andrew 2015), ATF6B is activated by cleavage in response to endoplasmic reticulum (ER) stress (Haze et al. 2001). In unstressed cells, ATF6B spans the ER membrane where its lumenal domain probably forms a complex with HSPA5 (BiP, GRP78). During ER stress, HSPA5 dissociates from ATF6B, exposing Golgi localization signals in the lumenal domain of ATF6B and causing ATF6B to traffic to the Golgi membrane. The Golgi-resident proteases MBTPS1 (S1P) and MBTPS2 (S2P) cleave ATF6B and release the cytoplasmic (N-terminal) domain, which contains a transcription activation domain, a bZIP dimerization domain, and a nuclear localization signal (Haze et al. 2001). N-glycosylation in the lumenal domain of ATF6B is required for cleavage (Guan et al. 2009). The cytoplasmic fragment transits to the nucleus where it acts as a weak transcription activator (Haze et al. 2001). By forming heterodimers with the strong activator ATF6, ATF6B may act as an inhibitory modulator of ATF6 (Thuerauf et al. 2004, Thuerauf et al. 2007). Deletion of the ER (C-terminal) domain of ATF6B in HEK293 cells causes increased production of membrane proteins, possibly due to constitutive transit of the N-terminal domain of ATF6B to the nucleus and activation of genes (Choi et al. 2025).
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