GRP78 Is a Targetable Receptor on Cancer and Stromal Cells

Glucose-Regulated Protein 78 (GRP78), also known as BiP (Binding Immunoglobulin Protein), is a member of the Hsp70 family of chaperone proteins that is essential for embryonic development. GRP78 is highly conserved across species, and is localized primarily in the endoplasmic reticulum, where it regulates protein folding and activates the unfolded protein response pathway (UPR) during stress conditions [6]. Under normal conditions, GRP78 binds to and inactivates the ER stress sensors ATF-6, PERK and IRE1.