FIGURE 7.

Phospho-Thr-120 limits the Mst1 attenuation of androgen-mediated and AR-dependent gene expression. A and B, PSA promoter reporter activity (p61-Luc) in C4-2 (A) and in LNCaP (B) cells that were transiently cotransfected with p61-Luc reporter and Vector, Mst1-WT, or the Mst1-T120A mutant construct followed by androgen induction in serum-starved conditions. Luciferase reporter assays were performed at 36 h post-transfection. The data normalized to the vector control were presented as luciferase activity. Data are represented as mean ± S.E. C, co-IP and WB analysis of Mst1 and endogenous AR interaction in C4-2 cells expressing transient Mock (Vec), Myc-Mst1-WT, or the Myc-Mst1-T120A mutant. Co-IP with anti-Myc antibody and WB analysis with an antibody to corresponding proteins was performed. The values of AR in the Myc-Mst1 immune complex were normalized to the Mst1 precipitant, and the data were expressed as percent (%) increase relative to vector control set to 0%. D, ChIP assay. C4-2 cells were transiently transfected with vector (Vec), Mst1-WT, or the Mst1-T12A mutant for 48 h. The ChIP assay was performed at 6 h after androgen (10 nm, R1881) treatment in serum-depleted conditions. Semiquantitative PCR was performed using a primer set covering the androgen response element core (AREc) region of the PSA promoter. The values of bond DNA were normalized to the input and expressed as percent (%) reduction. Data are representative of multiple experiments. E, model summarizes the conclusion of this study. P, phosphorylation.