Figure 4.

Analysis of the activation of PI3-kinase in MSV-β cells. (A) MSV-MDCK, MSV-β, and MSV-βΔCD-GFP cells were lysed, and p85 was immunoprecipitated from 1 mg of total cell lysates. The amount of tyrosine phosphorylated p85 in the immunoprecipitates was normalized to total p85 detected by immunoblotting with anti-phosphotyrosine and anti-p85 antibodies, respectively. The graph represents mean ± SD from three independent experiments. (B) Colocalization (arrowheads) of PH-Akt-GFP and Na,K-β (stained with anti-Na,K-β antibody followed by anti-Cy3 antibody) in MSV-MDCK and MSV-β cells. Bar, 25 μm.