Dynamic changes in complexes of IRE1α, PERK, and ATF6α during endoplasmic reticulum stress.

ABSTRACT: The endoplasmic reticulum (ER) localized unfolded protein response (UPR) sensors, IRE1α, PERK, and ATF6α, are activated by the accumulation of misfolded proteins in the ER. It is unclear how the endogenous UPR sensors are regulated by both ER stress and the ER luminal chaperone BiP, which is a negative regulator of UPR sensors. Here we simultaneously examined the changes in the endogenous complexes of UPR sensors by blue native PAGE immunoblotting in unstressed and stressed cells. We found that all three UPR sensors exist as preformed complexes even in unstressed cells. While PERK complexes shift to large complexes, ATF6α complexes are reduced to smaller complexes on ER stress. In contrast, IRE1α complexes were not significantly increased in size on ER stress, unless IRE1α is overexpressed

SUBMITTER: Sundaram A 

PROVIDER: S-EPMC5994896 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature