by PhilipJ on 4 December 2008
When cells are challenged with extreme heat, they build a collection of protective proteins called heat shock proteins (typically abbreviated as “Hsp” with the approximate molecular weight afterwards). Many of these proteins are chaperones that work to keep cellular proteins folded and active when conditions get bad. They also play important roles in the normal life of the cell, helping proteins fold and limiting the dangerous aggregation of immature proteins. Some of these proteins, such as Hsp70 and Hsp60 are general chaperones. Hsp90, on the other hand, plays a more specific role.
Hsp90 is a specialized chaperone that assists in the maturation of a select clientele of proteins. These proteins include over a hundred transcription factors and kinases, such as steroid receptors, mutant p53 protein, and the HER2 protein involved in breast cancer. So far, researchers have not discovered a unifying theme for this growing list of proteins, just that Hsp90 is essential for maintaining active forms of these proteins.
To find out more about Hsp90, click through to the PDB.