Immunoprecipitation of BIG1 and BIG2 complexes from HepG2 cells. Samples of proteins, cytosol (C) 2.6 mg, or microsomes (M) 0.4 mg, were immunoprecipitated (IP) by anti-BIG1 or anti-BIG2 IgG with or without the peptide used for immunization, as indicated. Immunoprecipitated proteins were separated by SDS/PAGE, and reacted on Western blots (WB) with anti-BIG1 or anti-BIG2 IgG. Data were similar in three experiments.