The subspine organization of actin fibers regulates the structure and plasticity of dendritic spines

Neuron. 2008 Mar 13;57(5):719-29. doi: 10.1016/j.neuron.2008.01.013.


Synapse function and plasticity depend on the physical structure of dendritic spines as determined by the actin cytoskeleton. We have investigated the organization of filamentous (F-) actin within individual spines on CA1 pyramidal neurons in rat hippocampal slices. Using two-photon photoactivation of green fluorescent protein fused to beta-actin, we found that a dynamic pool of F-actin at the tip of the spine quickly treadmilled to generate an expansive force. The size of a stable F-actin pool at the base of the spine depended on spine volume. Repeated two-photon uncaging of glutamate formed a third pool of F-actin and enlarged the spine. The spine often released this "enlargement pool" into the dendritic shaft, but the pool had to be physically confined by a spine neck for the enlargement to be long-lasting. Ca2+/calmodulin-dependent protein kinase II regulated this confinement. Thus, spines have an elaborate mechanical nature that is regulated by actin fibers.

Publication types

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

MeSH terms

  • Actin Cytoskeleton / chemistry
  • Actin Cytoskeleton / physiology
  • Actins / chemistry*
  • Actins / physiology*
  • Animals
  • Dendritic Spines / chemistry*
  • Dendritic Spines / physiology*
  • Humans
  • Neuronal Plasticity / physiology*
  • Organ Culture Techniques
  • Rats
  • Rats, Sprague-Dawley


  • Actins