Abstract
Cell motility necessitates the rapid formation and disassembly of cell adhesions. We have studied adhesions in a highly motile melanoma cell line using various biochemical approaches and microscopic techniques to image close adhesions. We report that WM-1617 melanoma cells contain at least two types of close adhesion: classic focal adhesions and more extensive, irregularly shaped adhesions that tend to occur along lamellipodial edges. In contrast to focal adhesions, these latter adhesions are highly dynamic and can be disassembled rapidly via protein kinase C (PKC) activation (e.g. by eicosanoid) and MARCKS phosphorylation. MARCKS overexpression, however, greatly increases the area of close adhesions and renders them largely refractory to PKC stimulation. This indicates that nonphosphorylated MARCKS is an adhesion stabilizer. Unlike focal adhesions, the dynamic adhesions contain alpha3 integrin and MARCKS, but they do not contain the focal adhesion marker vinculin. Overall, these results begin to define the molecular and functional properties of dynamic close adhesions involved in cell motility.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Animals
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Cell Adhesion*
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Cell Line, Tumor
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Cell Movement
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Humans
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Integrin alpha3 / metabolism
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Intercellular Junctions / physiology*
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Intracellular Signaling Peptides and Proteins / genetics
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Intracellular Signaling Peptides and Proteins / metabolism*
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Isoenzymes / genetics
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Isoenzymes / metabolism
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Melanoma / metabolism*
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Melanoma / pathology
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Melanoma, Experimental / metabolism*
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Melanoma, Experimental / pathology
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Membrane Proteins / genetics
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Membrane Proteins / metabolism*
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Mice
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Myristoylated Alanine-Rich C Kinase Substrate
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Paxillin / metabolism
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Protein Kinase C / genetics
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Protein Kinase C / metabolism
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Rats
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Tetradecanoylphorbol Acetate / metabolism
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Vinculin / metabolism
Substances
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Integrin alpha3
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Intracellular Signaling Peptides and Proteins
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Isoenzymes
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MARCKS protein, human
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Marcks protein, mouse
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Marcks protein, rat
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Membrane Proteins
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Paxillin
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Recombinant Fusion Proteins
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Myristoylated Alanine-Rich C Kinase Substrate
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Vinculin
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Protein Kinase C
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Tetradecanoylphorbol Acetate