Abstract
The small GTPase Rac1 has been implicated in regulation of cell migration and cell-cell adhesion in epithelial cells. Little is known, however, about the spatial and temporal coordination of Rac1 activity required to balance these competing processes. We fractionated endogenous Rac1-containing protein complexes from membranes of Madin-Darby canine kidney cells and identified three major complexes comprising a Rac1.PAK (p21-activated kinase) complex, and 11 S and 16 S Rac1 complexes. Significantly, Rac1 shifts from the 11 S to a 16 S particle during initiation of cell-cell adhesion. This shift may reflect a diffusion trapping mechanism by which these Rac1 complexes are localized to cadherin-mediated cell-cell contacts through an interaction with annexin II.
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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Actins / metabolism*
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Animals
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Annexin A1 / metabolism
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Annexin A2 / metabolism
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Cadherins / metabolism
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Cell Adhesion / physiology
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Cell Fractionation
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Cell Line
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Cell Membrane / metabolism*
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Chromones / metabolism
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Dogs
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Enzyme Inhibitors / metabolism
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Epithelial Cells / metabolism*
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Intercellular Junctions / metabolism*
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Macromolecular Substances
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Morpholines / metabolism
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Phosphatidylinositol 3-Kinases / metabolism
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Phosphoinositide-3 Kinase Inhibitors
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rac1 GTP-Binding Protein / genetics
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rac1 GTP-Binding Protein / metabolism*
Substances
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Actins
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Annexin A1
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Annexin A2
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Cadherins
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Chromones
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Enzyme Inhibitors
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Macromolecular Substances
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Morpholines
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Phosphoinositide-3 Kinase Inhibitors
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2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
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rac1 GTP-Binding Protein