HSPA5 and infection: When the ER homeostasis was interrupt by a series of stressors such as chemical toxicant, imbalance of ER calcium levels, glucose deprivation, lipid influx, and vital infection in vitro and vivo, the ER stress sensor glucose regulated protein (GRP78/Bip, Hspa5) triggered pathway termed unfolded protein response (UPR) was activated to cope with this stress[27], [28].