TTP interacts with ERα, PR, GR and AR in vivo. Endogenous ERα (A), PR (B), AR (C) and GR (C) were immunoprecipitated from protein extracts prepared from MCF-7 cells using specific antibodies. Immunoprecipitated proteins were resolved by PAGE, and the binding of TTP was visualized by Western blot. The input lane represents 10% of the protein extract used in the coimmunoprecipitation assays. IP: immunoprecipitation, WB: Western blot.