title: Negative regulation of T cell antigen receptor signal transduction by hematopoietic tyrosine phosphatase (HePTP).
abstract: The hematopoietic tyrosine phosphatase (HePTP) is predominantly expressed in thymocytes and T lymphocytes and at lower levels in other hematopoietic cells. Expression of the gene is enhanced by the T cell growth factor interleukin-2, suggesting a role for HePTP in T cell proliferation or differentiation. We report that HePTP blocks T cell antigen receptor (TCR)-induced transcriptional activation of a reporter gene driven by a nuclear factor of activated T cells(NFAT)/AP-1 element taken from the interleukin-2 gene promoter. This effect was specific to HePTP and was abolished by a mutation (C270S) that impaired its phosphatase activity. Co-expression of HePTP also reduced TCR-induced activation of the mitogen-activated protein kinase Erk2 and the TCR-induced appearance of phosphorylated Erk. In contrast, HePTP did not affect the activation of the N-terminal c-Jun kinase, Jnk. Together these findings suggest that HePTP plays an active negative role in TCR signaling by dephosphorylating one or several signaling molecules between the receptor and the mitogen-activated protein kinase pathway.
authors.affiliation: Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, California 92121, USA.
authors.forename: M
authors.initials: M
authors.lastname: Saxena
authors.forename: S
authors.initials: S
authors.lastname: Williams
authors.forename: J
authors.initials: J
authors.lastname: Gilman
authors.forename: T
authors.initials: T
authors.lastname: Mustelin
mesh_terms: D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004789:Enzyme Activation; D017930:Genes, Reporter; D006801:Humans; D007376:Interleukin-2 / Q000235:genetics / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D019169:Jurkat Cells; D019950:Mitogen-Activated Protein Kinase 1; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D010766:Phosphorylation; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000502:physiology*; D054558:Protein Tyrosine Phosphatases, Non-Receptor; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D015398:Signal Transduction; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation
chemical_list: D004268:DNA-Binding Proteins; D007376:Interleukin-2; D047908:Intracellular Signaling Peptides and Proteins; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D011948:Receptors, Antigen, T-Cell; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; C509249:PTPN6 protein, human; C502159:PTPN7 protein, human; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; D054558:Protein Tyrosine Phosphatases, Non-Receptor