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. 2007 May 29;404(Pt 3):449–458. doi: 10.1042/BJ20070003

Figure 7. Comparison of the relative levels of expression and activity of different class IA PI3K isoforms.

Figure 7

(A) Western blotting using isoform-specific antibodies was used to compare the levels of expression of class IA p110 isoforms in different cell types: lane 1, J774.2; lane 2, 3T3-L1 fibroblasts; lane 3, 3T3-L1 adipocytes; lane 4, CHO-IR; lane 5, HepG2. For p110α detection, total class IA activity was immunoprecipitated from 200 μg of lysate using an antibody recognizing the p85α adapter subunit, and recombinant protein was loaded as a control (0.2 μg, lane marked +). For p110β and p110δ detection, 20 μg of total cell lysate was loaded in each case. (B–E) Total class IA activity was immunoprecipitated from 20 μg of lysate from the indicated cell type using an antibody recognizing the p85α adapter subunit. PI3K activity was then assayed in the presence of 100 nM of the indicated inhibitor. Cell types were J774.2 (B), 3T3-L1 fibroblasts (C), 3T3-L1 adipocytes (D), CHO-IR (E) and HepG2 (F). Results are expressed relative to the activity in the presence of DMSO and are means±S.E.M. for three independent determinations. WORT, wortmannin.