Hydrogen peroxide in the ER: A tale of triage

Abstract Oxidative protein folding in the endoplasmic reticulum (ER) is a significant source of hydrogen peroxide (H2O2). For correct protein folding the redox state of the ER must be efficiently regulated. As such, several mechanisms with varying degrees of overlap manage the redox state of the ER. H2O2 also functions as a second messenger playing a role in most aspects of cellular physiology and pathology, requiring tight control of the concentration and flux of H2O2. Bestetti et al. have demonstrated a role for Aquaporin 11 in transport of H2O2 out of the ER.