Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2014 May 20;5:233. doi: 10.3389/fmicb.2014.00233

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

Copyright © 2014 Chan.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

PMC Copyright notice

Proposed mechanisms of E1/E2 activation of UPR. E1 and E2 are targeted and mature in the endoplasmic reticulum (ER) to form non-covalently-bonded heterodimers and disulphide-bonded aggregates (pink arrows, 1). The E2 aggregates distract BiP from PERK (purple arrow), allowing PERK oligomerization and activation (brown arrows, 2). Retrotranslocated (3) and cytosolic E1/E2 from surplus protein synthesis (4) can also activate the unfolded protein response (UPR) by perturbation of proteasomal function (Ub, polyubiquitin). Conversely, cytosolic E1/E2 can bind to the cytoplasmic domain of PERK and inhibit its activation (red cross, 5). Direct binding of E1 and E2 aggregates to the luminal domain of IRE1 can also activate UPR (6). Red asterisk, activation by phosphorylation.