Heat shock 70 kDa protein 1B

Heat shock 70 kDa protein 1B (HSPA1B) is a molecular chaperone that orchestrates protein quality control through cycles of ATP binding and hydrolysis. It maintains proteome integrity by promoting both refolding of misfolded proteins and their targeted degradation in partnership with co-chaperones such as HSP40s, BAG proteins, and STUB1 (UniProt: P0DMV9). The protein's acetylation state determines whether it favors refolding or degradation pathways, and it additionally regulates centrosome function during mitosis and modulates TGF-beta signaling through SMAD3 degradation.

HSPA1B is widely expressed and critical for cellular stress responses across diverse tissues. Its normal function encompasses protection of the proteome during cellular stress, folding of newly synthesized polypeptides, and quality control mechanisms essential for cell viability (UniProt: P0DMV9).

In Alzheimer's Disease, HSPA1B is significantly upregulated in post-mortem AD brain tissue compared to age-matched controls, with a mean log2 fold-change of +0.66 (Chaparral AD proteomics). This upregulation suggests enhanced protein quality control responses in AD brain, potentially reflecting attempts to mitigate proteotoxic stress associated with amyloid and tau pathology. The elevation was measured across subcellular fractions in TMT-labeled quantitative proteomics of human tissue.