HSP90: Family Members
Hsp90 visualized on Bouin’s fixed paraffin embedded backskin sections of transgenic mice, using Anti-Hsp90 (polyclonal)
The HSP90 family of proteins consists of molecular chaperones of approximately 90 kDa in size. According to Chen and co-workers, the HSP90 proteins can be divided in four subclasses, HSP90AA, HSP90AB, HSP90B, and TRAP 26. The human HSP90 gene family encodes at least five members (Table 2), with the exception of HSP90N originally termed Hsp89-α-δ-N 27 that has been found as being a chimera of two genes with its principal part identical to HSPC1 26. In zebrafish, three isoforms of Hsp90 can be found 28,29, while the nematode Caenorhabditis elegans and the fruit fly D. melanogaster contain only one Hsp90 homolog. In the yeast Saccharomyces cerevisiae, Hsp90 proteins are encoded by two genes, HSC82 and HSP82 30, while in the fungus Candida albicans one Hsp90 homolog is expressed in the cytoplasm 31. A detailed description of pro- and eukaryotic HSP90 family members is given in Table 2 and the following page.
