Hsp90 antibody [2D12]

The 90kDa molecular chaperone family comprises several proteins including the 90kDa heat shock protein, Hsp90 and the 94kDa glucose regulated protein, grp94 which are major molecular chaperones of the cytosol and of the endoplasmic reticulum. In mammalian cells there are at least two Hsp90 isoforms, Hsp90a and hsp90s which are encoded by separate genes. The amino acid sequence of human and yeast Hsp90a is 85% and 90% homologous to that of Hsp90s respectively. All known members of the Hsp90 protein family are highly conserved, especially in the N terminal and C terminal regions which have been shown to contain independent chaperone sites with different substrate specificity. These ubiquitous and highly conserved proteins account for 1-2% of all cellular proteins in most cells. Hsp90 is part of the cell's powerful network of chaperones to fight the deleterious consequences of protein unfolding caused by nonphysiological conditions. However, in the absence of stress, Hsp90 is a necessary component of fundamental cellular processes such as hormone signaling and cell cycle control. In this context several key regulatory proteins such as steriod receptors, cell cycle kinases involved in signal transduction and p53 have been identified as substrates of Hsp90. It has been suggested that Hsp90 acts as a capacitor for morphological evolution by buffering widespread variation, which may affect morphogenic pathways.