The leukocyte common antigen, CD45 and other protein tyrosine phosphatases in hematopoietic cells.
Numerous protein tyrosine phosphatases have been characterized that are expressed by hematopoietic-derived cells. CD45, a transmembrane protein tyrosine phosphatase expressed by all nucleated cells of hematopoietic origin, has been a prototype for studying the function of these enzymes. In T lymphocytes, CD45 serves to dephosphorylate and activate members of the Src-tyrosine kinase family. Without CD45 function, T cells cannot respond to antigen. Therefore, CD45 functions positively to regulate lymphocyte activation. The characteristics of other protein tyrosine phosphatases found in hematopoietic-derived cells suggests that they are also essential in regulating cell differentiation and activation.
Woodford-Thomas
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Howard Hughes Medical Institute, Washington University School of Medicine, St Louis, MO 63110.
Thomas
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D000818:Animals; D006412:Hematopoietic Stem Cells / Q000201:enzymology*; D006801:Humans; D017493:Leukocyte Common Antigens / Q000737:chemistry / Q000502:physiology*; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D013379:Substrate Specificity; D013601:T-Lymphocytes / Q000201:enzymology / Q000276:immunology / Q000502:physiology*
D011948:Receptors, Antigen, T-Cell; D011505:Protein-Tyrosine Kinases; D017493:Leukocyte Common Antigens; D017027:Protein Tyrosine Phosphatases