FIG. 6.

TSA enhances the interaction between HIF-1α and HSP70. A. HIF-1α interacts with HSP70. RCC4-VHL⁻ cells were treated with increasing concentrations of TSA for 4 h, and cell lysates were immunoprecipitated (IP) with anti-HIF-1α monoclonal antibodies. The precipitate was immunoblotted with anti-HIF-1α and anti-HSP70. B. HSP70 interacts with HIF-1a. Cells were treated as described for panel A, but lysates were precipitated with anti-HSP-70 monoclonal antibodies. C. TSA treatment increases HIF-1α in lysate pellets. VHL⁻ cells were treated for 6 h in the presence or absence of MG132 and TSA. The cell lysates were centrifuged, and the cell pellets were resuspended in loading buffer and analyzed by Western blotting. D. TSA treatment enhances HSP90 acetylation. RCC4-VHL⁻ cells were treated with TSA (600 nM) for 6 h followed by immunoprecipitation with anti-HSP90 antibodies. Whole-cell lysates and immunoprecipitation results were analyzed by Western blotting utilizing anti-HSP90 and anti-acetylated lysine (a-AcLys) antibodies. E. TSA treatment decreases the interaction between HSP90 and HIF-1α. RCC4-VHL⁻ cells were incubated with TSA (600 nM) for 6 h followed by immunoprecipitation with anti-HIF-1α antibodies. The immunoprecipitation results was analyzed by Western blotting using anti-HIF-1α and anti-HSP90 antibodies.