Rabbit Anti-Human HSP90B1 polyclonal antibody for IHC-P, WB. Heat shock protein (HSP) molecular chaperones are environmental stressinducible gene products. The human HSP 90 family includes 17 genes that fall into four classes: HSP90AA, HSP90AB, HSP90B and TRAP. HSP 90?, also designated HSP90B, HSP 84 and HSPC2, is a cytosolic protein that participates in signaling pathways with PKC ? to protect cells from external damage, particularly in heat shock-mediated events. GRP 94 (glucose regulated protein 94 kDa) , also known as tumor rejection antigen 1 (TRA1) , ECGP and GP96, localizes to the ER, is highly expressed in BGC-823 human gastric carcinoma cells and is upregulated in human endothelial cells in response to hypoxia by HIF-1.