Application
Lysates prepared from HeLa cells stimulated with PMA were resolved by SDS-PAGE on a 10% polyacrylamide gel and transferred to PVDF. Membranes were either left untreated (1-10) or treated with lambda phosphatase (11), blocked with a 3% low-fat milk-TBST buffer overnight at 4°C, and incubated with 0.50 µg/ml PKCgamma [pT514] antibody for two hours at room temperature in a 3% BSA-TBST buffer, following prior incubation with: no peptide (1, 10, 11), the non-phosphopeptide corresponding to the immunogen (2), a generic phosphothreonine containing peptide (3), the phosphopeptide immunogen (4), or, the phosphopeptide corresponding to the immunogen from other PKC isoforms (5-9). After washing, membranes were incubated with goat F(ab)2 anti-rabbit IgG alkaline phosphatase and signals were detected. The data show that the peptide corresponding to PKCgamma [pS514] blocks the antibody signal and that the peptides corresponding to PKC isoforms alpha [pT497], betaI&II [pT500], delta [pT507], epsilon [pT710] and theta [pT538] did not block the antibody signal, thereby demonstrating the specificity of the antibody. The data also show that phosphatase stripping eliminates the signal, verifying that the antibody is phospho-specific.