DEMONSTRATION OF SELECTIVE PROTEIN COMPLEXES OF P53 WITH 73-KDA HEAT-SHOCK COGNATE PROTEIN, BUT NOT WITH 72-KDA HEAT-SHOCK PROTEIN IN HUMANTUMOR-CELLS

It has been demonstrated that p53, especially, mutant p53 (mp53), make s protein complexes with major heat shock proteins hsp72/hsc73. Howeve r, there is no direct evidence showing whether hsp72 or hsc73 could bi nd preferentially to p53. In the present study, using TYKnu human ovar ial carcinoma cells and monoclonal antibodies reacting specifically to hsp72/hsc73, we were able to find the selective protein complex forma tion with p53, presumably mp53, and hsc73, but not in the case of p53 and hsp72. The p53-hsc73 protein complexes dissociate with the additio n of ATP, indicating that the dissociation is dependent upon the ATP-h ydrolysis. These data suggest that hsc73 rather than hsp72 plays an im portant role in the yet undefined mechanism of disregulated cell growt h control by mp53.