antiphosphotyrosine

Antiphosphotyrosine, in common usage referred to as anti-phosphotyrosine antibodies, are antibodies raised against the phosphorylated form of the amino acid tyrosine. They are used as research tools to detect protein tyrosine phosphorylation, a reversible modification catalyzed by protein tyrosine kinases and removed by tyrosine phosphatases. Phosphotyrosine signaling underlies many cellular processes, including growth factor signaling, immune receptor signaling, and cell differentiation, making reliable detection of this modification important for studying signal transduction.

Most antiphosphotyrosine antibodies are monoclonal or polyclonal and are designed to recognize the phosphotyrosine moiety, often in the context of surrounding amino acids. Some antibodies detect free phosphotyrosine, while others recognize phosphotyrosine within particular peptide sequences. In practice, these antibodies are applied in Western blotting, immunoprecipitation, immunofluorescence, immunohistochemistry, and enzyme-linked immunosorbent assays, and are used to monitor global or site-specific tyrosine phosphorylation in cells and tissues. They also enable enrichment of phosphotyrosine-containing proteins for proteomic analyses by affinity purification.

Limitations include potential cross-reactivity and context dependence, as antibody binding can vary with the peptide sequence surrounding the phosphotyrosine and with fixation or denaturation conditions. Appropriate controls, such as treatment with protein tyrosine phosphatases or using phosphotyrosine-free peptides, are advised to validate specificity. Antiphosphotyrosine antibodies remain foundational tools for mapping signaling networks and assessing dynamic responses to stimuli in research settings.