A Septin-Dependent Diffusion Barrier at Dendritic Spine Necks

Excitatory glutamatergic synapses at dendritic spines exchange and modulate their receptor content via lateral membrane diffusion. Several studies have shown that the thin spine neck impedes the access of membrane and solute molecules to the spine head. However, it is unclear whether the spine neck...

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Bibliographic Details
Published in:PloS one 2014-12, Vol.9 (12), p.e113916-e113916
Main Authors: Ewers, Helge, Tada, Tomoko, Petersen, Jennifer D, Racz, Bence, Sheng, Morgan, Choquet, Daniel
Format: Article
Language:English
Subjects:
Animals
Barriers
Biology and Life Sciences
Cells, Cultured
Cytoskeleton
Dendritic spines
Dendritic Spines - metabolism
Dendritic structure
Diffusion
Diffusion barriers
Diffusion rate
Fluorescent Antibody Technique
Gene expression
Glutamatergic transmission
GTP Phosphohydrolases - metabolism
Lateral diffusion
Membrane proteins
Membranes
Microscopy, Electron, Scanning
Molecular chains
Neck
Neurons - metabolism
Proteins
Rats
Rats, Sprague-Dawley
Receptors
Recovery (Medical)
Ribonucleic acid
RNA
RNA Interference
RNA-mediated interference
Septin
Septins - genetics
Septins - metabolism
Spine
Synapses
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Summary:Excitatory glutamatergic synapses at dendritic spines exchange and modulate their receptor content via lateral membrane diffusion. Several studies have shown that the thin spine neck impedes the access of membrane and solute molecules to the spine head. However, it is unclear whether the spine neck geometry alone restricts access to dendritic spines or if a physical barrier to the diffusion of molecules exists. Here, we investigated whether a complex of septin cytoskeletal GTPases localized at the base of the spine neck regulates diffusion across the spine neck. We found that, during development, a marker of the septin complex, Septin7 (Sept7), becomes localized to the spine neck where it forms a stable structure underneath the plasma membrane. We show that diffusion of receptors and bulk membrane, but not cytoplasmic proteins, is slower in spines bearing Sept7 at their neck. Finally, when Sept7 expression was suppressed by RNA interference, membrane molecules explored larger membrane areas. Our findings indicate that Sept7 regulates membrane protein access to spines.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0113916