Dendritic Spine Morphology Determines Membrane-Associated Protein Exchange between Dendritic Shafts and Spine Heads

Hugel, Sylvain ; Abegg, Mathias ; de Paola, Vincenzo ; Caroni, Pico ; Gähwiler, Beat H. ; McKinney, R. Anne

In: Cerebral Cortex, 2008, vol. 19, no. 3, p. 697-702

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    The purpose of this study was to examine whether variability in the shape of dendritic spines affects protein movement within the plasma membrane. Using a combination of confocal microscopy and the fluorescence loss in photobleaching technique in living hippocampal CA1 pyramidal neurons expressing membrane-linked GFP, we observed a clear correlation between spine shape parameters and the diffusion and compartmentalization of membrane-associated proteins. The kinetics of membrane-linked GFP exchange between the dendritic shaft and the spine head compartment were slower in dendritic spines with long necks and/or large heads than in those with short necks and/or small heads. Furthermore, when the spine area was reduced by eliciting epileptiform activity, the kinetics of protein exchange between the spine compartments exhibited a concomitant decrease. As synaptic plasticity is considered to involve the dynamic flux by lateral diffusion of membrane-bound proteins into and out of the synapse, our data suggest that spine shape represents an important parameter in the susceptibility of synapses to undergo plastic change