Fig. 7. Co-immunoprecipitation of PPP4c with proteins previously identified in the SMN protein complex. HeLa cells expressing CFP-SMN were used for immunoadsorption of SMN and HeLa cells transfected with vector expressing GFP were used in controls. Supernatant (S) and pellet (P) fractions were obtained by centrifugation following immunoadsorption from cell lysates (L) using anti-GFP-Sepharose (protein G), which readily interacts with both CFP and GFP. Proteins in the lysate (10 µl), supernatant (10 µl) and pellet (recovered from 500 µl) fractions were analysed by SDS-PAGE and subsequent immunoblotting with anti-GFP (A), anti-Gemin2 (B), anti-Gemin3 (C), anti-Gemin4 (D) and anti-PPP4c (E) antibodies. The 50 kDa bands in the pellet fractions of A are caused by the presence of large amounts of the antibody heavy chain.