FIGURE 1.

HDAC9 interacts with ATDC. A, silver-stained SDS-PAGE of the immunopurified FLAG- and HA-tagged HDAC9-containing complexes. Control, immunopurified samples prepared in parallel from HeLa cells expressing the GFP protein. B, HeLa cells were transfected with plasmids encoding FLAG-tagged HDAC9 and HA-tagged ATDC. Whole cell lysates were immunoprecipitated and probed with FLAG-specific or HA-specific antibodies as indicated. C, HeLa cells were transfected with plasmids encoding FLAG-tagged HDAC7 or HDAC9 and HA-tagged ATDC. Whole cell lysates were immunoprecipitated and probed with FLAG-specific or HA-specific antibodies as indicated. D, top, HeLa cells were transfected with plasmids encoding full-length or deletion mutants of FLAG-tagged HDAC9 and HA-tagged ATDC. Western blot analysis was performed on the anti-FLAG immunoprecipitates with antibodies specific for HA. Levels of FLAG-tagged HDAC9 and HA-tagged ATDC were determined by Western blot analysis of cell extracts using antibodies specific for FLAG or HA, respectively. Bottom, a schematic diagram (not drawn to scale) of HDAC9 and three HDAC9 deletion mutants. Ser²¹⁸ and Ser⁴⁴⁸ (S218 and S448) are serine phosphorylation sites. For simplicity, the FLAG portions of the fusion proteins are not shown. The ability of each FLAG-HDAC9 fusion protein to bind HA-ATDC is indicated (plus and minus signs). E, HeLa cell lysates were incubated with preimmune serum (mock IP) or the anti-ATDC antibody. Precipitated materials were analyzed by Western blotting using either anti-HDAC9 or anti-ATDC antibodies. IP, immunoprecipitation; IB, immunoblot.