Once Chinese hamster K12 cells are starved from glucose， the synthesis of GRP （glucose-regulated protein） expressed. HSPA5 also called BiP， is part of the HSP70 family and plays a role in the folding and assembly of proteins in the endoplasmic reticulum. HSPA5 plays a key role in monitoring protein transport through the cell.
HSPA5 is a stress response protein which is induced by agents or conditions that adversely affect endoplasmic reticulum function. HSPA5 is crucial for the proper glycosylation， folding as well as for the maintenance of cell homeostasis and the prevention of apoptosis. HSPA5 is differentially expressed in the dorsolateral prefrontal cortex from patients with schizophrenia. HSPA5 guides posttranslational hepatitis B virus large envelope protein import into the mammalian ER. HSPA5 actively regulates multiple malignant phenotypes， including cell growth， migration， and invasion.
