(a) COS1 cells were cotransfected with H6- or Flag-tagged CtBP1, CtBP(T176E) or CtBP(T176A) expression constructs, as indicated. Proteins were precipitated with anti-Flag agarose and analyzed by western blot with a H6 antibody. Expression of transfected proteins in the lysates is shown below. (b) COS1 cells were cotransfected with T7 tagged TGIF, Pc2, or MITR, together with a control vector, Flag-CtBP1 or CtBP(T176E) expression constructs. Proteins were precipitated with anti-Flag agarose and analyzed by western blot with a T7 antibody. Expression in the lysates is shown below.