CHOP

Inositol-requiring protein 1/IRE1 alpha (also called Endoplasmic Reticulum to Nucleus Signaling 1/ERN1; predicted mol wt 110 kDa) is a serine-threonine protein kinase/endoribonuclease which plays a highly critical role in unfolded protein response/UPR signaling, a mechanism by which eukaryotic cells sense and deal with ER stress. The latter triggers growth arrest and apoptosis in cells with misfolded proteins.