Dynamic localization of G-actin during membrane protrusion in neuronal motility

Curr Biol. 2013 Jun 17;23(12):1046-56. doi: 10.1016/j.cub.2013.04.057. Epub 2013 Jun 6.


Background: Actin-based cell motility is fundamental for development, function, and malignant events in eukaryotic organisms. During neural development, axonal growth cones depend on rapid assembly and disassembly of actin filaments (F-actin) for their guided extension to specific targets for wiring. Monomeric globular actin (G-actin) is the building block for F-actin but is not considered to play a direct role in spatiotemporal control of actin dynamics in cell motility.

Results: Here we report that a pool of G-actin dynamically localizes to the leading edge of growth cones and neuroblastoma cells to spatially elevate the G-/F-actin ratio that drives membrane protrusion and cell movement. Loss of G-actin localization leads to the cessation and retraction of membrane protrusions. Moreover, G-actin localization occurs asymmetrically in growth cones during attractive turning. Finally, we identify the actin monomer-binding proteins profilin and thymosin β4 as key molecules that localize actin monomers to the leading edge of lamellipodia for their motility.

Conclusions: Our results suggest that dynamic localization of G-actin provides a novel mechanism to regulate the spatiotemporal actin dynamics underlying membrane protrusion in cell locomotion and growth cone chemotaxis.

Publication types

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

MeSH terms

  • Actins / metabolism*
  • Animals
  • Cell Line, Tumor
  • Cell Membrane / metabolism*
  • Cell Movement
  • Chemotaxis*
  • Growth Cones / metabolism*
  • Neurons / metabolism
  • Neurons / physiology*
  • Profilins / metabolism
  • Pseudopodia / metabolism*
  • Thymosin / genetics
  • Thymosin / metabolism*
  • Xenopus laevis


  • Actins
  • Profilins
  • thymosin beta(4)
  • Thymosin