Abstract
Lymphocyte membrane rafts contain molecules critical for immunoreceptor signaling. Here, we report identification of a new raft-associated adaptor protein LIME (Lck-interacting molecule) expressed predominantly in T lymphocytes. LIME becomes tyrosine phosphorylated after cross-linking of the CD4 or CD8 coreceptors. Phospho-LIME associates with the Src family kinase Lck and its negative regulator, Csk. Ectopic expression of LIME in Jurkat T cells results in an increase of Csk in lipid rafts, increased phosphorylation of Lck and higher Ca2+ response to CD3 stimulation. Thus, LIME appears to be involved in regulation of T cell activation by coreceptors.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Vesicular Transport / genetics
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Adaptor Proteins, Vesicular Transport / immunology*
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Adaptor Proteins, Vesicular Transport / metabolism
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Amino Acid Sequence
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CD4 Antigens / immunology*
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CD8 Antigens / immunology*
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CSK Tyrosine-Protein Kinase
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DNA, Complementary
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Databases, Protein
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Humans
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Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / metabolism
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Membrane Microdomains / immunology*
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Molecular Sequence Data
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Phosphorylation
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Protein-Tyrosine Kinases / metabolism
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src-Family Kinases
Substances
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Adaptor Proteins, Vesicular Transport
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CD4 Antigens
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CD8 Antigens
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DNA, Complementary
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Lck-interacting protein, mouse
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Protein-Tyrosine Kinases
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CSK Tyrosine-Protein Kinase
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Lymphocyte Specific Protein Tyrosine Kinase p56(lck)
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src-Family Kinases
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CSK protein, human