Hsp90(90kDaheatshockprotein)isamolecularchaperonethataidsproteinfoldingandqualitycontrolforalargenumberofclientproteins.FunctionalHsp90operatesasdimerandhasintrinsicATPaseactivity.TheHsp90dimeractsinconcertwithotherchaperones(e.g.Hsp70)andisregulatedbyanumberofco-chaperones/accessoryproteins(e.g.Hop,cdc37).Hsp90hasbeenshowntointeractwith>100proteinsandsomenotableclientsincludekinases(e.g.Raf-1),nuclearhormonereceptors(e.g.estrogenreceptors),transcriptionfactors(e.g.p53),GPCRs(e.g.CB2receptors)andionchannels(e.g.CFTR).Inhumans,theHsp90betaisoformisconstitutivelyexpressedwhereastheHsp90alphaisoformsisexpressedunderstressconditions.Hsp90playsanimportantroleinsometumorcelltypesbyst
ABIlisingmutatedoncogenicproteins.InhibitionofHsp90betafunctionhasbeenshowntoplayaroleintum
Origenesisanddiseaseprogression.