Fig. 4. TGIF recruits mSin3 to Smad2. COS-1 cells were transfected with expression vectors encoding Smad2, myc-Sin3, and HA-TGIF or a control vector. TGFß was added for 1 h before cell lysis, as indicated. Proteins were precipitated via the myc-epitope present on mSin3 and analyzed by Western blotting using a Smad2-specific antiserum. mSin3-associated Smad2 is indicated by an arrow. A portion of the lysate was analyzed for expression of transfected proteins (below).