WB (peptide competition) analysis of HEK293 cells transiently transfected with WT PTEN (Lane 1, 3-6) or mutant S385A (Lane 2) using GTX13590 PTEN (phospho Ser385) antibody prior incubated with the non-phosphopeptide corresponding to the immunogen (Lane 3), a generic phosphoserine-containing peptide (Lane 4), or the phosphopeptide immunogen (Lane 5). The data show that only the immunogen phosphopeptide blocks the signal, demonstrating the specificity of the antibody. The membrane treated with phosphatase (Lane 6) eliminates the signal further verifying that the antibody is phospho-specific.