Cordon-bleu is an actin nucleation factor and controls neuronal morphology

Cell. 2007 Oct 19;131(2):337-50. doi: 10.1016/j.cell.2007.08.030.


Despite the wealth of different actin structures formed, only two actin nucleation factors are well established in vertebrates: the Arp2/3 complex and formins. Here, we describe a further nucleator, cordon-bleu (Cobl). Cobl is a brain-enriched protein using three Wiskott-Aldrich syndrome protein homology 2 (WH2) domains for actin binding. Cobl promotes nonbundled, unbranched filaments. Filament formation relies on barbed-end growth and requires all three Cobl WH2 domains and the extended linker L2. We suggest that the nucleation power of Cobl is based on the assembly of three actin monomers in cross-filament orientation. Cobl localizes to sites of high actin dynamics and modulates cell morphology. In neurons, induction of both neurites and neurite branching is dramatically increased by Cobl expression-effects that critically depend on Cobl's actin nucleation ability. Correspondingly, Cobl depletion results in decreased dendritic arborization. Thus, Cobl is an actin nucleator controlling neuronal morphology and development.

Publication types

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

MeSH terms

  • Actin-Related Protein 2-3 Complex / physiology
  • Actins / metabolism*
  • Amino Acid Sequence
  • Animals
  • Cells, Cultured
  • Chlorocebus aethiops
  • Cytoskeletal Proteins
  • Humans
  • Mice
  • Microfilament Proteins
  • Molecular Sequence Data
  • Neurites / physiology
  • Neurons / cytology
  • Neurons / metabolism*
  • Neurons / physiology
  • Phylogeny
  • Protein Structure, Tertiary
  • Proteins / genetics
  • Proteins / physiology*
  • Rats


  • Actin-Related Protein 2-3 Complex
  • Actins
  • Cobl protein, mouse
  • Cytoskeletal Proteins
  • Microfilament Proteins
  • Proteins