Peptide Competition Extracts prepared from PC12 cells treated with nocozadole were resolved by SDS-PAGE on a 10% polyacrylamide gel and transferred to PVDF. Membranes were blocked with a 5% BSA-TBST buffer for one hour at room temperature, then incubated with FAK [pS732] antibody for two hours at room temperature in a 1% Milk-TBST buffer, following prior incubation with: no peptide (1), the non-phosphopeptide corresponding to the immunogen (2), a generic phospho-serine containing peptide (3), or, the phosphopeptide immunogen (4). After washing, membranes were incubated with goat F(ab’)2 anti-rabbit IgG HRP conjugate and bands were detected using the Pierce SuperSignal‘ method. The data show that only the peptide corresponding to FAK [pS732] blocks the antibody signal, thereby demonstrating the specificity of the antibody. The phospho signal also was absent after lambda ( ) phosphatase stripping (data not shown), verifying that the antibody is phospho specific.