Anti-protein tyrosine phosphatase non-receptor type 22 antibodies are used for the immunodetection of the protein encoded by the PTPN22 gene. In humans, the canonical protein has a reported length of 807 amino acid residues and a mass of 91.7 kDa. Its subcellular localization is in the cytoplasm. Alternative splicing is reported to yield 6 different isoforms for this protein. It is reported to be expressed in bone marrow, B and T-cells, PBMCs, natural killer cells, monocytes, dendritic cells and neutrophils. A member of the Protein-tyrosine phosphatase protein family, it is known to act as negative regulator of T-cell receptor (TCR) signaling by direct dephosphorylation of the Src family kinases LCK and FYN, ITAMs of the TCRz/CD3 complex, as well as ZAP70, VAV, VCP and other key signaling molecules. Post-translational modifications have been described, including phosphorylation. Other names for this target antigen include LYP1, LYP2, PEP, PTPN22.5, PTPN22.6, PTPN8, tyrosine-protein phosphatase non-receptor type 22, and LYP. Gene orthologs have been identified in the mouse, rat, bovine, frog, chimpanzee and chicken species.