FIG. 9.

Loss of SF-1 SUMOylation enhances interaction with CDK7, a kinase required for S203 phosphorylation. (A) Lysates of Y1 cells (1 × 10⁶) stably expressing WT-SF-1, K194R, or 2KR were subjected to Ni²⁺ bead pulldown, followed by anti-CDK7, anti-SRC-1, or anti-SF-1 immunoblotting (IB). Whole-cell lysates from these cell lines were subjected to anti-SF-1 and anti-β-actin immunoblotting as controls. (B) Y1 cells (1 × 10⁶) stably expressing WT-SF-1 or K194R were treated with either roscovitine (Ros) or U0126 for 1 h. The cell lysates were harvested and directly subjected to immunoblotting or Ni²⁺ bead pulldown, followed by immunoblotting with the indicated antibodies.