Pathways for Sensing and Responding to Hydrogen Peroxide at the Endoplasmic Reticulum.

The endoplasmic reticulum (ER) has emerged as a source of hydrogen peroxide (HO) and a hub for peroxide-based signaling events. Here we outline cellular sources of ER-localized peroxide, including sources within and near the ER. Focusing on three ER-localized proteins-the molecular chaperone BiP, the transmembrane stress-sensor IRE1, and the calcium pump SERCA2-we discuss how post-translational modification of protein cysteines by HO can alter ER activities.