Abstract
Surface expression of the CD45 tyrosine phosphatase is essential for the T cell antigen receptor (TCR) to couple optimally with its second messenger pathways. CD45 may be required to dephosphorylate a TCR-activated protein tyrosine kinase, which then transduces an activation signal from the TCR. A chimeric molecule that contained extracellular and transmembrane sequences from an allele of a major histocompatibility class I molecule and cytoplasmic sequences of CD45 restored TCR signaling in a CD45-deficient mutant T cell line. Thus, expression of the complex extracellular domain of CD45 is not required for the TCR to couple to its signaling machinery.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Base Sequence
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Cell Line
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Cell Membrane / metabolism
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Cytoplasm / metabolism
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Enzyme Activation
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Humans
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Inositol Phosphates / metabolism
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Leukocyte Common Antigens / genetics
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Leukocyte Common Antigens / metabolism*
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Membrane Proteins / metabolism
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Molecular Sequence Data
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Phosphorylation
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Protein-Tyrosine Kinases / metabolism
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Receptors, Antigen, T-Cell / metabolism*
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Recombinant Fusion Proteins / metabolism
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Second Messenger Systems
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Signal Transduction*
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T-Lymphocytes / metabolism*
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Transfection
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Tyrosine / metabolism
Substances
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Inositol Phosphates
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Membrane Proteins
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Receptors, Antigen, T-Cell
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Recombinant Fusion Proteins
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Tyrosine
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Protein-Tyrosine Kinases
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Leukocyte Common Antigens