1994 Fiscal Year Final Research Report Summary
Cloning and analysis of protein tyrosine phosphatases expressed in lymphoid organs.
| Project/Area Number |
05670301
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Immunology
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| Research Institution | Osaka University |
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Principal Investigator |
OGATA Masato Osaka University Medical School, assistant professor, 医学部, 助手 (60224094)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Tyrosine phosphatase / Lymphocytes / Thymus / mRPTP-sigma / PTP36 / PTPBR7 / DPZPTP |
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| Research Abstract |
Reversible phosphorylation of tyrosine residues plays a crucial regulatory role in various cellular events including differentiation and proliferation of lymphocytes. To screen PTPs (protein tyrosine phosphatases) in the murine lymphoid organs, we amplified the cDNA by PCR with degenerative primers. We found seven novel murine PTPs and further analyzed four of them. mRPTP-sigma(formerly called as PTPT9) was a transmembrane PTP,whose extracellular domain was composed of lg-like and FN-lll-like domains as N-CAM family cell-adhesion molecules. At least three alternatively spliced transcripts (T,B,and S) were observed and mRPTP-sigma T was dominant in thymus whereas mRPTP-sigma B was dominant in brain. PTP36 had a C-terminal phosphatase domain and an N-terminal domain with homology to band 4.1, a cytoskeletal-associated protein. In addition, we found a putative SH3-binding motif in PTP36.mRPTP-sigma and PTP36 were expressed both in immature thymocytes and thymic stroma cells. In developing T lymphocytes, mRPTP-sigma and PTP36 were expressed dominantly in CD4^-CD8^- and CD4^+CD8^+ subpopulations, respectively. Developmentally regulated expression of mRPTP-sigma and PTP36 suggests its involvement in the control of T lymphocyte differentiation. DPZPTP (formerly called as PTPST8) was a cytoplasmic PTP with five GLGF repeats, which had been found in a Drosophila tumor suppresser gene, dlg. In the thymus, DPZPTP was expressed dominantly in the stroma fraction. PTPBR7 was a novel receptor PTP with only one cytoplasmic phosphatase domain and its extracellular domain revealed no obvious structural similarity to known molecules. Thus, PTPBR7 defined a new subfamily of receptor-type protein tyrosine phosphatase. PTPBR7 was expressed almost exclusively in the brain and especially in the cerebellum. The unique structure of PTPBR7 and its predominant expression in the brain suggested its crucial regulatory role in neuronal cells.
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Research Products
(6 results)
