Fig. 1.

Schematic illustration of endoplasmic reticulum (ER) stress and the unfolded protein response (UPR). ATF, activating transcription factor; BiP, immunoglobulin heavy-chain-binding protein [glucose regulated protein-78 (GRP78)]; EDEM, ER degradation enhancing α-mannosidase-like protein; eIF2α, eukaryotic initiation factor 2α; GADD34, growth arrest and DNA damage protein 34; IRE, inositol-requiring enzyme 1 (IRE-1); PERK, PKR-like ER kinase; XBP-1, X-box binding protein 1. [Adapted from Isler et al. (24) with permission from the American Society for microbiology.]