Fig. 2. PTEN2, Baz and aPKC are associated in a protein complex. (A) Extracts of untransfected S2 cells and S2 cells transfected with PTEN2 alone or with PTEN2 and Baz together were subjected to western blot analysis with an antibody directed against the C terminus of PTEN2. The antibody recognizes a 65 kDa protein that is strongly increased in S2 cells transfected with PTEN2. A band of the same size is detected when PTEN2 is translated in vitro in a reticulocyte lysate system (PTEN2 ivt). An additional band of 85 kDa (asterisk) is probably a crossreacting protein unrelated to PTEN. (B) Extracts from wild-type embryos were subjected to immunoprecipitation with an antibody directed against Baz or with the corresponding preimmune serum. Immunoprecipitates were probed on western blots with antibodies against PTEN (top panel) and Baz (bottom panel). (C) Extracts of untransfected S2 cells and S2 cells co-transfected with PTEN2 or PTEN3 together with Baz were subjected to immunoprecipitation with either PTEN antibody or with the corresponding pre-immune serum. Immunoprecipitates were analyzed by western blot with Baz antibody (top panel), PTEN antibody (middle panel) and aPKC antibody (bottom panel). Specific co-immunoprecipitation of Baz was detected only with PTEN2 but not with PTEN3. Endogenous aPKC co-immunoprecipitates with PTEN2 but not with PTEN3 in the presence of Baz. Western blots of the cell extracts used for immunoprecipitation are shown on the right (Input).