PTPRF/LAR Antibody #17164

Receptor type protein tyrosine phosphatase F (PTPRF, LAR) is a transmembrane PTP that helps to regulate insulin signaling, cell proliferation and cell migration. The PTPRF protein is composed of an extracellular segment that contains several Ig-like and fibronectin (Fn-III) domains, a transmembrane region and a pair of cytoplasmic phosphatase domains (1,2). Functional studies reveal that the membrane-associated D1 phosphatase domain is responsible for substrate dephosphorylation, while the D2 domain is important for substrate specificity (3). PTPRF negatively regulates insulin signaling through dephosphorylation of insulin receptor and insulin receptor substrate (4). This phosphatase activates the pro-apoptotic DAPK serine/threonine kinase by removing a phosphate at Tyr491/492, while the kinase Src replaces the phosphate to inactivate DAPK at the same time it down regulates PTPRF expression (5). PTPRF is commonly found at focal adhesions where it interacts with liprin, which localizes the phosphatase to the membrane, and the Rac/Rho family GTPase Trio (6). Localization of PTPRF at adherens junctions results in PTPRF modification of β-catenin, which inhibits cell migration by limiting the amount of available cytosolic β-catenin (7).