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Thomas A Blanpied "PALM imaging of cytoskeletal dynamics inside spines"

Abstract :

Rapid regulation of ongoing actin polymerization within dendritic spines underlies diverse forms of synaptic plasticity.
 Indeed, among possible mechanisms for organizing the spine internal milieu, actin is uniquely capable of establishing the framework of spine components that control spine shape, synaptic receptor content, and numerous other functions directly determining synapse strength. To map the organization of actin dynamics within spines, we have used single-molecule tracking photoactivated localization microscopy (PALM) to measure the motion of individual actin molecules. This approach revealed inward actin flow from broad areas of the spine plasma membrane, as well as a dense central core of heterogeneous filament orientation, and actin filaments in the spine neck oriented both into and out of the spine. The velocity of single actin molecules along filaments was elevated near the postsynaptic density, but also at discrete points distant from the synapse. We conclude that actin polymerization is initiated at many well-separated foci within spines. This organization may be necessary for the specific adjustment of synaptic molecular content that underlies functional plasticity.

Selected publications

Blanpied, T. A., Kerr, J. D., Ehlers, M. D. (2008) Structural plasticity with preserved topology in the postsynaptic protein network. Proc Natl Acad Sci. 105: 12587-12592.
Lu, J., Helton, T. D., Blanpied, T. A., Racz, B., Newpher, T. M., Weinberg, R. J., and Ehlers, M. D. (2007) Postsynaptic positioning of endocytic zones and AMPA receptor cycling by physical coupling of dynamin-3 to homer. Neuron 55: 874-889.
Blanpied, T. A., Clarke, R. J., and Johnson, J. W. (2005) Amantadine inhibits NMDA receptors by accelerating channel closure during channel block. J. Neurosci.25: 3312-3322.

Valentin Nagerl