Repression of Heat Shock Transcription Factor HSF1 Activation by HSP90 (HSP90 Complex) that Forms a Stress-Sensitive Complex with HSF1

摘要: Heat shock and other proteotoxic stresses cause accumulation of nonnative proteins that trigger activation heat protein (Hsp) genes. A chaperone/Hsp functioning as repressor transcription factor (HSF) could make hsp genes dependent on unfolding. In a novel in vitro system, which human HSF1 can be activated by protein, heat, geldanamycin, addition Hsp90 inhibits activation. Reduction the level but not Hsp/c70, Hop, Hip, p23, CyP40, or Hsp40 dramatically activates HSF1. vivo, geldanamycin under conditions it is an Hsp90-specific reagent. Hsp90-containing complex present unstressed cell dissociates during stress. We conclude Hsp90, itself and/or associated with multichaperone complexes, major