Super-resolution imaging reveals that AMPA receptors inside synapses are dynamically organized in nanodomains regulated by PSD95.
The spatiotemporal organization of neurotransmitter receptors in postsynaptic membranes is a fundamental determinant of synaptic transmission and information processing by the brain. Using four independent super-resolution light imaging methods and EM of genetically tagged and endogenous receptors, we show that, in rat hippocampal neurons, AMPARs are often highly concentrated inside synapses into a few clusters of ∼70 nm that contain ∼20 receptors. AMPARs are stabilized reversibly in these nanodomains and diffuse freely outside them. Nanodomains are dynamic in their shape and position within synapses and can form or disappear within minutes, although they are mostly stable for up to 1 h. AMPAR nanodomains are often, but not systematically, colocalized with clusters of the scaffold protein PSD95, which are generally of larger size than AMPAR nanoclusters. PSD95 expression level regulates AMPAR nanodomain size and compactness in parallel to miniature EPSC amplitude. Monte Carlo simulations further indicate the impact of AMPAR concentration in clusters on the efficacy of synaptic transmission. The observation that AMPARs are highly concentrated in nanodomains, instead of diffusively distributed in the PSD as generally thought, has important consequences on our understanding of excitatory neurotransmission. Furthermore, our results indicate that glutamatergic synaptic transmission is controlled by the nanometer-scale regulation of the size of these highly concentrated nanodomains.
University of Bordeaux, Interdisciplinary Institute for Neuroscience, and Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France.
Deepak
D
Nair
Eric
E
Hosy
Jennifer D
JD
Petersen
Audrey
A
Constals
Gregory
G
Giannone
Daniel
D
Choquet
Jean-Baptiste
JB
Sibarita
D000200:Action Potentials / Q000187:drug effects / Q000235:genetics; D000818:Animals; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D000076122:Disks Large Homolog 4 Protein; D004622:Embryo, Mammalian; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000235:genetics; D005260:Female; D018756:GABA Antagonists / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology; D000072233:Homer Scaffolding Proteins; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D049329:Nanostructures; D009474:Neurons / Q000166:cytology*; D010852:Picrotoxin / Q000494:pharmacology; D021381:Protein Transport / Q000235:genetics / Q000502:physiology; D051381:Rats; D018091:Receptors, AMPA / Q000378:metabolism*; D013269:Stochastic Processes; D013569:Synapses / Q000378:metabolism* / Q000648:ultrastructure*; D013570:Synaptic Membranes / Q000378:metabolism* / Q000648:ultrastructure
D015220:Calcium Channels; D002352:Carrier Proteins; D000076122:Disks Large Homolog 4 Protein; D018756:GABA Antagonists; D049452:Green Fluorescent Proteins; D000072233:Homer Scaffolding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D010852:Picrotoxin; D018091:Receptors, AMPA; C491911:Cacng2 protein, rat; C501449:Dlg4 protein, rat