T-cell protein tyrosine phosphatase: A role in inflammation and autoimmunity

A cDNA of PTPN2 encoding for T-cell protein tyrosine phosphate (TC-PTP) was isolated and characterized as long as 20 years ago. However, findings suggesting a potentially exciting role of this enzyme in general autoimmunity have only recently been obtained. Genome-wide association scans of the human genome revealed the involvement of PTPN2 in susceptibility to a several autoimmune disorders such as Crohn’s disease, type 1 diabetes, and Graves’ disease. Functional studies in immune cells revealed a key role of this enzyme in down-regulation of cytokine expression and inflammatory response, which provides an essential background to explaining the pathophysiological role of TC-PTP in autoimmunity. Thus, in addition to PTPN22, PTPN2 is likely to represent a second member of the broad family of non-receptor PTPs contributing to general autoimmunity.