Heat shock protein family A member 9 (HSPA9)

Heat shock protein family A member 9 (HSPA9), also known as mortalin or GRP75, is a mitochondrial chaperone protein belonging to the Hsp70 family. Predominantly localized in mitochondria but also present in the endoplasmic reticulum, cytosol, plasma membrane, nucleus, and extracellularly, HSPA9 is essential for mitochondrial protein import, proper protein folding, and quality control. It also contributes to the biogenesis of mitochondrial iron-sulfur clusters, modulates apoptosis (by interacting with calcium channels and apoptosis regulators), and protects against oxidative and proteotoxic stress. HSPA9 plays key roles in cell proliferation, differentiation, and senescence, and its dysfunction is linked to cancer, aging, genetic syndromes, and neurodegeneration. Overexpression and abnormal localization of HSPA9 are frequently observed in tumors, suggesting it as a potential therapeutic target, though with notable challenges due to its vital cellular functions.

Other names

GRP75PBP7475 kDa glucose-regulated proteinStress-70 protein, mitochondrialmt-HSP70HSPA9BMortalinMortalin2Mot-2Mthsp75Peptide-binding protein 74MOTEpididymis secretory sperm binding protein Li 124mHeat shock 70 kDa protein 9Mitochondrial Hsp70

Inhibition of chaperone function leads to proteotoxic stress, mitochondrial dysfunction, and selective tumor cell death. Modulation of mitochondrial import/function, proliferation, and cell survival pathways.