Cayman Chemical | GRP94 Monoclonal Antibody (Clone 9G10) | Description • GP96; Glucose Regulated Protein 94

Antigen: purified recombinant GPR94 protein · Host: rat, clone 9G10 · Isotype: IgG2a · Application(s): WB. IP, and flow cytometry · Glucose regulated protein 94 (GRP94) is a constitutively expressed endoplasmic reticulum (ER) lumenal protein that is up-regulated in response to cellular stress such as heat shock, oxidative stress or glucose depletion. GRP94 is thought to play a role in protein translocation to the ER, in their subsequent folding and assembly, and in regulating protein secretion.¹ GRP94 also plays a role in antigen presentation by accessing the endogenous pathway and eliciting specific cytotoxic T lymphocyte (CTL) responses to chaperone bound peptides via the major histocompatibility complex (MHC) class I pathway.² GRP94 is a member of the Hsp90 family of stress proteins and shares sequence homology with its cytosolic equivalent, Hsp90.³ Both Hsp90 and GRP94 are calcium binding proteins.⁴ Despite sharing 50% sequence homology over its N domains and complete conservation in its ligand binding domains with Hsp90, GRP94, and Hsp90 differ in their interactions with regulatory ligands as GRP94 has weak ATP binding and hydrolysis activity.⁵ GRP94 exists as a homodimer and the two subunits interact at two distinct intermolecular sites, C-terminal dimerization domains and the N-terminal interacts with the middle domain of opposing subunits.⁶ GRP94 contains a carboxy terminal KDEL (Lys-Asp-Glu-Leu) sequence which is believed to aid in its retention in the ER.⁷

1 Ruddon, R.W., Bedows, E. Assisted protein folding. J Biol Chem 272(6) 3125-3128 (1997).

2 Srivastava, P.K., Udono, H., Blachere, N.E., et al. Heat shock protein transfer peptides during antigen processing and CTL priming. Immunogenetics 39(2) 93-98 (1994).

3 Mazzarella, R.A., Green, M. ERp99, an abundant, conserved glycoprotein of the endoplasmic reticulum, is homologous to the 90-kDa heat shock protein (hsp90) and the 94-kDa glucose regulated protein (GRP94). J Biol Chem 262(18) 8875-8883 (1987).

4 Kang, H.S., Welch, W.J. Characterization and purification of the 94-kDa glucose-regulated protein. J Biol Chem 266(9) 5643-5649 (1991).

5 Soldano, K.L., Jivan, A., Nicchitta, C.V., et al. Structure of the N-terminal domain of GRP94. Basis for ligand specificity and regulation. J Biol Chem 278(48) 48330-48338 (2003).

6 Chu, F., Maynard, J.C., Chiosis, G., et al. Identification of novel quaternary domain interactions in the Hsp90 chaperone, GRP94. Protein Science 15 1260-1269 (2006).

7 Peter, F., Van, P.N., Söling, H. Different sorting of Lys-Asp-Glu-Leu proteins in rat liver. J Biol Chem 267(15) 10631-10637 (1992).

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