Piccolo Directs Activity Dependent F-Actin Assembly from Presynaptic Active Zones via Daam1

PLoS One. 2015 Apr 21;10(4):e0120093. doi: 10.1371/journal.pone.0120093. eCollection 2015.

Abstract

The dynamic assembly of filamentous (F) actin plays essential roles in the assembly of presynaptic boutons, the fusion, mobilization and recycling of synaptic vesicles (SVs), and presynaptic forms of plasticity. However, the molecular mechanisms that regulate the temporal and spatial assembly of presynaptic F-actin remain largely unknown. Similar to other F-actin rich membrane specializations, presynaptic boutons contain a set of molecules that respond to cellular cues and trans-synaptic signals to facilitate activity-dependent assembly of F-actin. The presynaptic active zone (AZ) protein Piccolo has recently been identified as a key regulator of neurotransmitter release during SV cycling. It does so by coordinating the activity-dependent assembly of F-Actin and the dynamics of key plasticity molecules including Synapsin1, Profilin and CaMKII. The multidomain structure of Piccolo, its exquisite association with the AZ, and its ability to interact with a number of actin-associated proteins suggest that Piccolo may function as a platform to coordinate the spatial assembly of F-actin. Here we have identified Daam1, a Formin that functions with Profilin to drive F-actin assembly, as a novel Piccolo binding partner. We also found that within cells Daam1 activation promotes Piccolo binding, an interaction that can spatially direct the polymerization of F-Actin. Moreover, similar to Piccolo and Profilin, Daam1 loss of function impairs presynaptic-F-actin assembly in neurons. These data suggest a model in which Piccolo directs the assembly of presynaptic F-Actin from the AZ by scaffolding key actin regulatory proteins including Daam1.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Actins / metabolism*
  • Animals
  • COS Cells
  • Cell Membrane / metabolism
  • Chlorocebus aethiops
  • Cytoskeletal Proteins / chemistry
  • Cytoskeletal Proteins / physiology*
  • Female
  • Intracellular Signaling Peptides and Proteins / chemistry
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Mice
  • Neuropeptides / chemistry
  • Neuropeptides / physiology*
  • Presynaptic Terminals / metabolism*
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Protein Multimerization
  • Protein Transport
  • Pseudopodia / metabolism
  • Rats, Sprague-Dawley
  • Stress Fibers / metabolism

Substances

  • Actins
  • Cytoskeletal Proteins
  • Daam1 protein, rat
  • Intracellular Signaling Peptides and Proteins
  • Neuropeptides
  • Pclo protein, rat