The regulation of antigen-receptor signaling by protein tyrosine phosphatases: a hole in the story.
Antigen-receptor signaling requires Src-family kinases to initiate tyrosine phosphorylation. CD45 dephosphorylates the inhibitory site in Src-family kinases before antigen-receptor engagement and thus serves to 'prime' the kinases. It has been unclear why CD45 does not also dephosphorylate 'activated' kinases or motifs within the cytoplasmic domains of antigen-receptors and thus prevent signal transduction. Recent reports raise the possibility that CD45 is excluded from engaged antigen-receptors by mechanisms that may include the formation of lipid microdomains.
Thomas
M L
ML
Howard Hughes Medical Institute, Box 8118, Departments of Pathology andMolecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA. mthomas@pathbox.wustl.edu
D000818:Animals; D002448:Cell Adhesion; D006801:Humans; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008213:Lymphocyte Activation; D008563:Membrane Lipids / Q000378:metabolism; D008954:Models, Biological; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
D008563:Membrane Lipids; D011948:Receptors, Antigen, T-Cell; D019061:src-Family Kinases; D017493:Leukocyte Common Antigens; D017027:Protein Tyrosine Phosphatases