Abstract
The avidity of integrin adhesion receptors for extracellular ligands is subject to dynamic regulation by intracellular programs that have yet to be elucidated. We describe here a protein, cytohesin-1, which specifically interacts with the intracellular portion of the integrin beta 2 chain (CD18). The molecule shows homology to the yeast SEC7 gene product and bears a pleckstrin homology (PH) domain. Overexpression of either the full-length cytohesin-1 or the SEC7 domain induces beta 2 integrin-dependent binding of Jurkat cells to ICAM-1, whereas expression of the isolated cytohesin-1 PH domain inhibits T cell receptor-stimulated adhesion. Similar inhibition is not exhibited by PH domains taken from other proteins, showing that the interaction is specific and that individual PH domains are capable of discriminating between alternative targets.
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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Amino Acid Sequence
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Base Sequence
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CD18 Antigens / genetics
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CD18 Antigens / metabolism
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Cell Adhesion Molecules / chemistry
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Cell Adhesion Molecules / metabolism
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Cell Adhesion Molecules / pharmacology*
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Cell Adhesion Molecules / physiology
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Cell Line / chemistry
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Cloning, Molecular
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Escherichia coli / genetics
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Guanine Nucleotide Exchange Factors
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HT29 Cells / physiology
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HeLa Cells / physiology
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Humans
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Intercellular Adhesion Molecule-1 / metabolism*
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Leukemia
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Lymphocyte Function-Associated Antigen-1 / metabolism*
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Molecular Sequence Data
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Protein Binding / drug effects
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Protein Binding / physiology
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Protein Structure, Tertiary
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Recombinant Proteins / genetics
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Sensitivity and Specificity
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Vaccinia virus / genetics
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Yeasts / chemistry
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Yeasts / genetics
Substances
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CD18 Antigens
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Cell Adhesion Molecules
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Guanine Nucleotide Exchange Factors
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Lymphocyte Function-Associated Antigen-1
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Recombinant Proteins
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cytohesin-1
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Intercellular Adhesion Molecule-1