PP2A, Abcam, ab32104

Our team performed a comprehensive review of the scientific literature to identify studies using antibodies against human Protein Phosphatase 2A (PP2A), followed by extraction and evaluation of available data according to the pAbmAbs rating criteria. In this study, Frohner et al. conducted a head-to-head comparison of eight commercially available antibodies against PP2A catalytic subunit phosphorylated at Tyr307 (PP2Ac pTyr307). Antibody performance was evaluated by WB and ELISA, with particular emphasis on specificity for Tyr307 phosphorylation versus other post-translational modifications, including Leu309 methylation. For WB experiments, antibodies were tested using lysates from stably HA-PP2AC-expressing NIH 3T3 cells, transiently transfected HEK293T cells, HAP1 cells, and primary mouse CD4+ T cells under multiple experimental conditions, including phosphatase treatment, modulation of PP2A methylation, kinase activation, and site-directed mutagenesis. Peptide ELISA was performed using synthetic PP2A C-terminal peptides carrying defined combinations of post-translational modifications. Detailed experimental procedures are provided in the original publication (see reference). This antibody, Abcam ab32104 (clone E155), does not specifically detect PP2AC pTyr307 over unmodified PP2AC in WB or ELISA, and the WB signal is unaffected by phosphatase treatment. In contrast, antibody recognition in both WB and ELISA is sensitive to the methylation state of the neighboring Leu309, with preferential detection of non-methylated PP2AC. Thus, the antibody should not be considered specific for PP2AC pTyr307 or as a pan-PP2A antibody.