Co-immunprecipitation of PP1 with HeLa nuclear PP1 binding and complex proteins. Antibodies were obtained for the proteins shown and immunoprecipitations performed. Immunoprecipitated proteins were run on SDS-PAGE, transferred to a membrane and probed with the same antibodies as indicated plus a pan PP1 antibody to determine if PP1 co-immunoprecipitates. The immunoprecipitating antibody is shown on the left and in all cases a pre-immune serum control was done in parallel (PIS). The blotting antibody it indicated on the right.