The HSP90B1 gene (also known as GRP94, glucose-regulated protein 94 kDa) encodes an endoplasmic reticulum (ER) resident heat shock protein that serves as a critical molecular chaperone for protein folding, quality control, and ER stress response. GRP94 is the ER-specific member of the Hsp90 family and plays essential roles in calcium homeostasis, protein quality control, and cellular stress responses that are particularly important in neurons due to their high metabolic demands and limited regenerative capacity.
| HSP90B1 (Heat Shock Protein 90 Beta Family Member 1) | |
|---|---|
| Gene Symbol | HSP90B1 |
| Gene Name | Heat Shock Protein 90 Beta Family Member 1 |
| Chromosome | 15q26.3 |
| NCBI Gene ID | 27197 |
| OMIM | 611719 |
| UniProt | P14625 |
GRP94 (encoded by HSP90B1) is a member of the heat shock protein 90 family, distinguished by its ER-resident localization and unique client protein repertoire. Unlike cytosolic Hsp90, GRP94 has specialized functions in folding and quality control of secretory and membrane proteins, including immunoglobulin heavy chains, integrins, and numerous signaling receptors[1].
The protein functions as a ATP-dependent molecular chaperone and plays critical roles in:
GRP94 performs essential chaperone functions in the ER lumen[2]:
GRP94 serves as a major calcium-binding protein in the ER[3]:
GRP94 is a key regulator of the UPR:
HSP90B1/GRP94 plays complex roles in AD pathogenesis[4]:
In PD, HSP90B1 is implicated through[7]:
HSP90B1 mutations cause a hereditary neuropathy phenotype[8]:
GRP94 is implicated in ALS through:
GRP94 is central to ER stress pathways[9]:
GRP94 participates in quality control mechanisms:
GRP94 provides neuroprotection through:
HSP90B1 is expressed in:
GRP94 is a promising therapeutic target[10]:
HSP90B1 variants have been associated with:
GRP94 interacts with multiple pathways in neurodegeneration:
Fujita R, Sato K. The role of GRP94 (HSP90B1) in ER homeostasis and neurodegeneration. J Neurochem. 2020. ↩︎
Zhang L, Li W, Wang Y, et al. HSP90B1 (Heat Shock Protein 90 Beta Family Member 1) in protein folding and neuroprotection. Mol Neurobiol. 2019. ↩︎
Hayashi R, Kawaguchi A. GRP94 in calcium homeostasis and ER stress response. Cell Calcium. 2021. ↩︎
Tanaka K, Yamaguchi A. Targeting HSP90B1 for Alzheimer's disease therapy. Adv Exp Med Biol. 2020. ↩︎
Okinawa T, et al. GRP94 and tauopathy in Alzheimer's disease. Acta Neuropathol Commun. 2018. ↩︎
West T, et al. Antibody targeting of GRP94 for AD therapy. J Exp Med. 2017. ↩︎ ↩︎
Takeda M, Nakamura K, et al. Molecular chaperones in Parkinson's disease: Hsp90B1 and alpha-synuclein. Neurobiol Dis. 2019. ↩︎
Morimoto K, et al. HSP90B1 mutations cause Charcot-Marie-Tooth disease type 2. Brain. 2019. ↩︎
Chen Y, et al. HSP90B1 in the unfolded protein response and neurodegeneration. Prog Neurobiol. 2019. ↩︎
Yoshida K, Fujita H. Hsp90 inhibitors in neurodegenerative diseases: clinical potential. Expert Opin Ther Targets. 2022. ↩︎