Arp2/3 ATP hydrolysis-catalysed branch dissociation is critical for endocytic force generation

Nat Cell Biol. 2006 Aug;8(8):826-33. doi: 10.1038/ncb1443. Epub 2006 Jul 23.


The Arp2/3 complex, which is crucial for actin-based motility, nucleates actin filaments and organizes them into y-branched networks. The Arp2 subunit has been shown to hydrolyse ATP, but the functional importance of Arp2/3 ATP hydrolysis is not known. Here, we analysed an Arp2 mutant in Saccharomyces cerevisiae that is defective in ATP hydrolysis. Arp2 ATP hydrolysis and Arp2/3-dependent actin nucleation occur almost simultaneously. However, ATP hydrolysis is not required for nucleation. In addition, Arp2 ATP hydrolysis is not required for the release of a WASP-like activator from y-branches. ATP hydrolysis by Arp2, and possibly Arp3, is essential for efficient y-branch dissociation in vitro. In living cells, both Arp2 and Arp3 ATP-hydrolysis mutants exhibit defects in endocytic internalization and actin-network disassembly. Our results suggest a critical feature of dendritic nucleation in which debranching and subsequent actin-filament remodelling and/or depolymerization are important for endocytic vesicle morphogenesis.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Actin-Related Protein 2 / genetics
  • Actin-Related Protein 2 / metabolism*
  • Actin-Related Protein 3 / genetics
  • Actin-Related Protein 3 / metabolism*
  • Actins / metabolism*
  • Adenosine Triphosphate / metabolism*
  • Catalysis
  • Endocytosis / physiology*
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Hydrolysis
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism
  • Microfilament Proteins / genetics
  • Microfilament Proteins / metabolism
  • Microscopy, Fluorescence
  • Models, Biological
  • Mutation / genetics
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Signal Transduction / physiology


  • Actin-Related Protein 2
  • Actin-Related Protein 3
  • Actins
  • Membrane Glycoproteins
  • Microfilament Proteins
  • Recombinant Fusion Proteins
  • Saccharomyces cerevisiae Proteins
  • plastin
  • Green Fluorescent Proteins
  • Adenosine Triphosphate