Nervous wreck and Cdc42 cooperate to regulate endocytic actin assembly during synaptic growth

J Neurosci. 2008 Aug 13;28(33):8316-25. doi: 10.1523/JNEUROSCI.2304-08.2008.

Abstract

Regulation of synaptic morphology depends on endocytosis of activated growth signal receptors, but the mechanisms regulating this membrane-trafficking event are unclear. Actin polymerization mediated by Wiskott-Aldrich syndrome protein (WASp) and the actin-related protein 2/3 complex generates forces at multiple stages of endocytosis. FCH-BIN amphiphysin RVS (F-BAR)/SH3 domain proteins play key roles in this process by coordinating membrane deformation with WASp-dependent actin polymerization. However, it is not known how other WASp ligands, such as the small GTPase Cdc42, coordinate with F-BAR/SH3 proteins to regulate actin polymerization at membranes. Nervous Wreck (Nwk) is a conserved neuronal F-BAR/SH3 protein that localizes to periactive zones at the Drosophila larval neuromuscular junction (NMJ) and is required for regulation of synaptic growth via bone morphogenic protein signaling. Here, we show that Nwk interacts with the endocytic proteins dynamin and Dap160 and functions together with Cdc42 to promote WASp-mediated actin polymerization in vitro and to regulate synaptic growth in vivo. Cdc42 function is associated with Rab11-dependent recycling endosomes, and we show that Rab11 colocalizes with Nwk at the NMJ. Together, our results suggest that synaptic growth activated by growth factor signaling is controlled at an endosomal compartment via coordinated Nwk and Cdc42-dependent actin assembly.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / chemistry
  • Actins / metabolism
  • Actins / physiology*
  • Animals
  • Animals, Genetically Modified
  • Cattle
  • Drosophila
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism
  • Drosophila Proteins / physiology*
  • Endocytosis / genetics
  • Endocytosis / physiology*
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Nerve Tissue Proteins / physiology*
  • Neuromuscular Junction / genetics
  • Neuromuscular Junction / metabolism
  • Neuromuscular Junction / physiology
  • Presynaptic Terminals / physiology
  • Protein Transport / genetics
  • Protein Transport / physiology
  • Synapses / genetics
  • Synapses / metabolism
  • Synapses / physiology*
  • Transforming Growth Factor beta / physiology
  • Wiskott-Aldrich Syndrome Protein / metabolism
  • Wiskott-Aldrich Syndrome Protein / physiology
  • cdc42 GTP-Binding Protein / physiology*

Substances

  • Actins
  • Drosophila Proteins
  • Nerve Tissue Proteins
  • Transforming Growth Factor beta
  • WASp protein, Drosophila
  • Wiskott-Aldrich Syndrome Protein
  • gbb protein, Drosophila
  • nwk protein, Drosophila
  • cdc42 GTP-Binding Protein