HSPA9 encodes a member of the heat shock protein 70 gene family. Stress-70 protein mitochondrial is primarily localized to the mitochondria but is also found in the endoplasmic reticulum, plasma membrane and cytoplasmic vesicles. This protein is a heat-shock cognate protein. Stress-70 protein mitochondrial plays a role in cell proliferation, stress response and maintenance of the mitochondria. A pseudogene of this gene is found on chromosome 2.