title: The FERM and PDZ domain-containing protein tyrosine phosphatases, PTPN4 and PTPN3, are both dispensable for T cell receptor signal transduction.
abstract: PTPN3 and PTPN4 are two closely-related non-receptor protein tyrosine phosphatases (PTP) that, in addition to a PTP domain, contain FERM (Band 4.1, Ezrin, Radixin, and Moesin) and PDZ (PSD-95, Dlg, ZO-1) domains. Both PTP have been implicated as negative-regulators of early signal transduction through the T cell antigen receptor (TCR), acting to dephosphorylate the TCRzeta chain, a component of the TCR complex. Previously, we reported upon the production and characterization of PTPN3-deficient mice which show normal TCR signal transduction and T cell function. To address if the lack of a T cell phenotype in PTPN3-deficient mice can be explained by functional redundancy of PTPN3 with PTPN4, we generated PTPN4-deficient and PTPN4/PTPN3 double-deficient mice. As in PTPN3 mutants, T cell development and homeostasis and TCR-induced cytokine synthesis and proliferation were found to be normal in PTPN4-deficient and PTPN4/PTPN3 double-deficient mice. PTPN13 is another FERM and PDZ domain-containing non-receptor PTP that is distantly-related to PTPN3 and PTPN4 and which has been shown to function as a negative-regulator of T helper-1 (Th1) and Th2 differentiation. Therefore, to determine if PTPN13 might compensate for the loss of PTPN3 and PTPN4 in T cells, we generated mice that lack functional forms of all three PTP. T cells from triple-mutant mice developed normally and showed normal cytokine secretion and proliferative responses to TCR stimulation. Furthermore, T cell differentiation along the Th1, Th2 and Th17 lineages was largely unaffected in triple-mutants. We conclude that PTPN3 and PTPN4 are dispensable for TCR signal transduction.
authors.affiliation: Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Bauler
authors.forename: Wiljan J A J
authors.initials: WJ
authors.lastname: Hendriks
authors.forename: Philip D
authors.initials: PD
authors.lastname: King
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D018345:Mice, Knockout; D017434:Protein Structure, Tertiary; D054589:Protein Tyrosine Phosphatase, Non-Receptor Type 3 / Q000235:genetics / Q000502:physiology*; D054590:Protein Tyrosine Phosphatase, Non-Receptor Type 4 / Q000235:genetics / Q000502:physiology*; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000502:physiology; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D013601:T-Lymphocytes / Q000502:physiology
chemical_list: D011948:Receptors, Antigen, T-Cell; D054589:Protein Tyrosine Phosphatase, Non-Receptor Type 3; D054590:Protein Tyrosine Phosphatase, Non-Receptor Type 4; D017027:Protein Tyrosine Phosphatases; C516657:Ptpn3 protein, mouse; C516659:Ptpn4 protein, mouse