The heat shock protein 90 antagonist geldanamycin alters chaperone association with p210bcr-abl and v-src proteins before their degradation by the proteasome

Several important signaling proteins including transcription factors and protein kinases depend on heat shock protein (Hsp)-90 for stability. p210 bcr-abl ,a protein expressed in chronic myelogenous leukemia, is functionally inhibited by the benzoquinone ansamycin herbimycin A. Benzoquinone ansamycins also bind to and inhibit the activity of Hsp90. We now demonstrate that p210 bcr-abl is complexed with Hsp90 and its