Combinatorial morphogenesis of dendritic spines and filopodia by SPAR and α-actinin2

Rap small GTPases regulate excitatory synaptic strength and morphological plasticity of dendritic spines. Changes in spine structure are mediated by the F-actin cytoskeleton, but the link between Rap activity and actin dynamics is unclear. Here, we report a novel interaction between SPAR, a postsyna...

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Bibliographic Details
Published in:Biochemical and biophysical research communications 2009-06, Vol.384 (1), p.55-60
Main Authors: Hoe, Hyang-Sook, Lee, Ji-Yun, Pak, Daniel T.S.
Format: Article
Language:English
Subjects:
Actin cytoskeleton
Actinin - genetics
Actinin - metabolism
Animals
Cercopithecus aethiops
COS Cells
Dendritic Spines - metabolism
Dendritic Spines - physiology
GTPase-Activating Proteins - genetics
GTPase-Activating Proteins - metabolism
Hippocampal neurons
Humans
Postsynaptic density
Pseudopodia - metabolism
Pseudopodia - physiology
Rap small GTPase
Rats
Structural plasticity
Two-Hybrid System Techniques
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Summary:Rap small GTPases regulate excitatory synaptic strength and morphological plasticity of dendritic spines. Changes in spine structure are mediated by the F-actin cytoskeleton, but the link between Rap activity and actin dynamics is unclear. Here, we report a novel interaction between SPAR, a postsynaptic inhibitor of Rap, and α-actinin, a family of actin-cross-linking proteins. SPAR and α-actinin engage in bidirectional structural plasticity of dendritic spines: SPAR promotes spine head enlargement, whereas increased α-actinin2 expression favors dendritic spine elongation and thinning. Surprisingly, SPAR and α-actinin2 can function in an additive rather than antagonistic fashion at the same dendritic spine, generating combination spine/filopodia hybrids. These data identify a molecular pathway bridging the actin cytoskeleton and Rap at synapses, and suggest that formation of spines and filopodia are not necessarily opposing forms of structural plasticity.
ISSN:0006-291X
1090-2104
DOI:10.1016/j.bbrc.2009.04.069