Heat Shock Protein 70 Family 9 (HSPA9)/GRP75//MOT2 [D9]

The Heat Shock Protein 70 family comprises four highly conserved proteins, HSP70, HSC70, HSPA9 (GRP75) and HSPA5 (GRP78), which serve a variety of roles. HSC70, HSPA9 and HSPA5 are constitutively expressed in primate cells. HSP 70 expression is strongly induced in response to heat stress. HSPA9 and HSPA5 are unresponsive to heat stress and are induced by glucose deprivation. HSPA9 expression is restricted to the mitochondrial matrix and aids in the translocation and folding of nascent polypeptide chains of both nuclear and mitochondrial origin. Studies show the overexpression of HSPA9 in multiple breast cancer carcinoma and downregulation of HSPA9 using shRNA or inhibition using MKT-077 significantly inhibited cancer cell proliferation and migration. With breast cancer being the most commonly diagnosed malignancy among females, researchers must continue to focus on potential targets and discover the mechanisms that contribute to breast cancer cell proliferation and metastasis. HSPA9 may be useful for breast cancer prognosis.