Abstract
Yeast actin patches are dynamic structures that form at the sites of cell growth and are thought to play a role in endocytosis. We used biochemical analysis and live cell imaging to investigate actin patch assembly in fission yeast Schizosaccharomyces pombe. Patch assembly proceeds via two parallel pathways: one dependent on WASp Wsp1p and verprolin Vrp1p converges with another dependent on class 1 myosin Myo1p to activate the actin-related protein 2/3 (Arp2/3) complex. Wsp1p activates Arp2/3 complex via a conventional mechanism, resulting in branched filaments. Myo1p is a weaker Arp2/3 complex activator that makes unstable branches and is enhanced by verprolin. During patch assembly in vivo, Wsp1p and Vrp1p arrive first independent of Myo1p. Arp2/3 complex associates with nascent activator patches over 6-9 s while remaining stationary. After reaching a maximum concentration, Arp2/3 complex patches move centripetally as activator proteins dissociate. Genetic dependencies of patch formation suggest that patch formation involves cross talk between Myo1p and Wsp1p/Vrp1p pathways.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Actin-Related Protein 2-3 Complex / chemistry
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Actin-Related Protein 2-3 Complex / isolation & purification
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Actin-Related Protein 2-3 Complex / metabolism*
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Actins / metabolism*
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Animals
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Cattle
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Cell Survival
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Microfilament Proteins / chemistry
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Microfilament Proteins / isolation & purification
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Microfilament Proteins / metabolism*
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Microscopy, Fluorescence
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Models, Biological
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Myosin Type I / chemistry
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Myosin Type I / isolation & purification
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Myosin Type I / metabolism*
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Protein Binding
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Protein Transport
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Recombinant Fusion Proteins / metabolism
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Schizosaccharomyces / cytology
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Schizosaccharomyces / metabolism*
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Schizosaccharomyces pombe Proteins / chemistry
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Schizosaccharomyces pombe Proteins / isolation & purification
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Schizosaccharomyces pombe Proteins / metabolism*
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Sequence Deletion
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Time Factors
Substances
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Actin-Related Protein 2-3 Complex
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Actins
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Microfilament Proteins
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Recombinant Fusion Proteins
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Schizosaccharomyces pombe Proteins
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Vrp1 protein, S pombe
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Wsp1 protein, S pombe
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Myosin Type I