Protoplasma

, Volume 226, Issue 1–2, pp 89–101

The WASP/Las17p-interacting protein Bzz1p functions with Myo5p in an early stage of endocytosis

  • A. Soulard
  • S. Friant
  • C. Fitterer
  • C. Orange
  • G. Kaneva
  • G. Mirey
  • B. Winsor
Article

DOI: 10.1007/s00709-005-0108-4

Cite this article as:
Soulard, A., Friant, S., Fitterer, C. et al. Protoplasma (2005) 226: 89. doi:10.1007/s00709-005-0108-4

Summary.

The formation of actin filaments is crucial for endocytosis and other interrelated cellular phenomena such as motility, polarized morphogenesis, and cytokinesis. In this paper we have investigated the role of the WASP/Las17-interacting protein Bzz1p in endocytosis and trafficking to the vacuole. We and others have recently shown that Bzz1p is an actin patch protein that interacts directly with Las17p via a SH3-polyproline interaction. Bzz1p functions with type I myosins to restore polarity of the actin cytoskeleton after NaCl stress. In an in vitro bead assay, GST-Bzz1p fusion protein triggers a functional actin polymerization machinery through its two C-terminal SH3 domains. In this paper we implicate Bzz1p with the type I myosins both in fluid-phase and in the internalization step of receptor-mediated endocytosis. As deduced from their localization as GFP fusions, the vacuolar delivery of endocytic and biosynthetic cargoes as well as the multivesicular body pathway appear unaffected. We further elucidate Bzz1p direct participation in actin polymerization by demonstrating that each of the SH3 domains of Bzz1p individually is able to trigger actin polymerization in a cell-free system dependent on Arp2/3, Las17p, Vrp1p, and the type I myosins. Taken together, our results show that Bzz1p participates, essentially via its SH3 domains, in early steps of endocytosis together with known actin nucleation activators.

Key words: Actin; Endocytosis; Saccharomyces cerevisiae; Actin patch protein Bzz1p; WASP-interacting protein; Type I myosin. 

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Copyright information

© Springer-Verlag/Wien 2005

Authors and Affiliations

  • A. Soulard
    • 1
  • S. Friant
    • 1
  • C. Fitterer
    • 1
  • C. Orange
    • 1
  • G. Kaneva
    • 1
  • G. Mirey
    • 1
  • B. Winsor
    • 1
  1. 1.Equipe Cytosquelette et Trafic Intracellulaire, Laboratoire Génétique Moléculaire, Génomique et Microbiologie, Unité Mixte de Recherche 7156 du Centre National de la Recherche Scientifique, Institut de Physiologie et Chimie BiologiqueStrasbourg

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