Interactions of WASp, myosin-I, and verprolin with Arp2/3 complex during actin patch assembly in fission yeast

J Cell Biol. 2005 Aug 15;170(4):637-48. doi: 10.1083/jcb.200502053. Epub 2005 Aug 8.

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

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin-Related Protein 2-3 Complex / chemistry
  • Actin-Related Protein 2-3 Complex / isolation & purification
  • Actin-Related Protein 2-3 Complex / metabolism*
  • Actins / metabolism*
  • Animals
  • Cattle
  • Cell Survival
  • Microfilament Proteins / chemistry
  • Microfilament Proteins / isolation & purification
  • Microfilament Proteins / metabolism*
  • Microscopy, Fluorescence
  • Models, Biological
  • Myosin Type I / chemistry
  • Myosin Type I / isolation & purification
  • Myosin Type I / metabolism*
  • Protein Binding
  • Protein Transport
  • Recombinant Fusion Proteins / metabolism
  • Schizosaccharomyces / cytology
  • Schizosaccharomyces / metabolism*
  • Schizosaccharomyces pombe Proteins / chemistry
  • Schizosaccharomyces pombe Proteins / isolation & purification
  • Schizosaccharomyces pombe Proteins / metabolism*
  • Sequence Deletion
  • Time Factors

Substances

  • Actin-Related Protein 2-3 Complex
  • Actins
  • Microfilament Proteins
  • Recombinant Fusion Proteins
  • Schizosaccharomyces pombe Proteins
  • Vrp1 protein, S pombe
  • Wsp1 protein, S pombe
  • Myosin Type I