Lsb1 Is a Negative Regulator of Las17 Dependent Actin Polymerization Involved in Endocytosis

  • Spiess M
  • de Craene J
  • Michelot A
 et al. 
  • 31

    Readers

    Mendeley users who have this article in their library.
  • 7

    Citations

    Citations of this article.

Abstract

The spatial and temporal regulation of actin polymerization is crucial for various cellular processes. Members of the Wiskott-Aldrich syndrome protein (WASP) family activate the Arp2/3-complex leading to actin polymerization. The yeast Saccharomyces cerevisiae contains only one WASP homolog, Las17, that requires additional factors for its regulation. Lsb1 and Lsb2/Pin3 are two yeast homologous proteins bearing an SH3 domain that were identified as Las17-binding proteins. Lsb2/Pin3 that promotes prion induction was suggested to link this prion formation to the actin cytoskeleton. However, the cellular role of Lsb1 and the molecular function of both Lsb1 and Lsb2 remain unknown. In this study, we show that Lsb1 and/or Lsb2 full-length proteins inhibit Las17-mediated actin polymerization in vitro, Lsb2 being a less potent inhibitor of Las17 activity compared to Lsb1. Addition of Lsb1 or Lsb2 to the corresponding full-length Lsb1/2 further inhibits Las17 activity. Lsb1 and Lsb2 form homo- and hetero-oligomeric complexes suggesting that these two proteins could regulate Las17 activity via dimerization or cooperative binding. In vivo, overexpressed Lsb1 and Lsb2 proteins cluster Las17-CFP in few cytoplasmic punctate structures that are also positive for other Arp2/3-dependent actin polymerization effectors like Sla1 or Abp1. But, only Lsb1 overexpression blocks the internalization step of receptor-mediated endocytosis. This shows a specific function of Lsb1 in endocytosis.

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • Johan De CraeneUniversité François-Rabelais

    Follow
  • Matthias Spiess

  • Alphée Michelot

  • Bruno Rinaldi

  • Aline Huber

  • David G. Drubin

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free