FIGURE 4.

SRC-2 interacts with and coactivates MEF2, GATA-4, and Tbx5. A, co-immunprecipitation (IP) analysis performed with the indicated antibodies or IgG controls in H9c2 cardiomyocyte whole cell lysates. Whole cell lysates for MEF2 and Tbx5 immunoprecipitations were isolated from H9c2 cells with endogenous protein. Whole cell lysates for GATA-4 IP were isolated from H9c2 cells infected with adenovirus for HA-SRC-2 or GATA-4 as indicated. Immunoblots were performed with the indicated antibodies. + indicates the removal of irrelevant lanes. All lanes shown are from a single gel. B–D, transactivation assays performed in HeLa cells on the ability of the indicated factors to activate luciferase activity driven by the promoters. SRC-2 or transcription factors were expressed from transiently transfected expression plasmids. RLU, relative luciferase units.