SNX9 Couples Actin Assembly to Phosphoinositide Signals and Is Required for Membrane Remodeling during Endocytosis

Defne Yarar, Clare M. Waterman-Storer, Sandra L. Schmid

Research output: Contribution to journalArticle

138 Scopus citations

Abstract

Multiple modes of endocytosis require actin-dependent remodeling of the plasma membrane; however, neither the factors linking these processes nor their mechanisms of action are understood. The sorting nexin, SNX9, localizes to clathrin-coated pits where it interacts with dynamin and functions in clathrin-mediated endocytosis. Here, we demonstrate that SNX9 also localizes to actin-rich structures implicated in fluid-phase uptake, including tubular membranes containing GPI-anchored proteins and dorsal membrane ruffles. Moreover, we show that SNX9 is critical for dorsal ruffle formation and for clathrin-independent, actin-dependent fluid-phase endocytosis. In vitro, SNX9 directly associates with N-WASP, an Arp2/3 complex activator, and stimulates N-WASP/Arp2/3-mediated actin assembly. SNX9-stimulated actin polymerization is greatly enhanced by PI4,5P2-containing liposomes, due in part to PI4,5P2-induced SNX9 oligomerization. These results suggest a mechanism for the spatial and temporal regulation of N-WASP-dependent actin assembly and implicate SNX9 in directly coupling actin dynamics to membrane remodeling during multiple modes of endocytosis.

Original languageEnglish (US)
Pages (from-to)43-56
Number of pages14
JournalDevelopmental cell
Volume13
Issue number1
DOIs
StatePublished - Jul 3 2007

Keywords

  • CELLBIO

ASJC Scopus subject areas

  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Developmental Biology
  • Cell Biology

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