ORCID Profile
0000-0003-4726-9763
Current Organisations
CNRS
,
Université de Bordeaux
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Publisher: Elsevier BV
Date: 04-2015
DOI: 10.1016/J.NEURON.2015.03.013
Abstract: PSD-95 is a prominent organizer of the postsynaptic density (PSD) that can present a filamentous orientation perpendicular to the plasma membrane. Interactions between PSD-95 and transmembrane proteins might be particularly sensitive to this orientation, as "long" cytoplasmic tails might be required to reach deeper PSD-95 domains. Extension/retraction of transmembrane protein C-tails offer a new way of regulating binding to PSD-95. Using stargazin as a model, we found that enhancing the apparent length of stargazin C-tail through phosphorylation or by an artificial linker was sufficient to potentiate binding to PSD-95, AMPAR anchoring, and synaptic transmission. A linear extension of stargazin C-tail facilitates binding to PSD-95 by preferentially engaging interaction with the farthest located PDZ domains regarding to the plasma membrane, which present a greater affinity for the stargazin PDZ-domain-binding motif. Our study reveals that the concerted orientation of the stargazin C-tail and PSD-95 is a major determinant of synaptic strength.
Publisher: Elsevier BV
Date: 09-2013
Publisher: Wiley
Date: 04-01-2013
Publisher: American Association for the Advancement of Science (AAAS)
Date: 16-02-2021
DOI: 10.1126/SCISIGNAL.ABB1953
Abstract: Blocking the constitutive activity of the ghrelin receptor impairs spatial and recognition memory.
Publisher: Elsevier BV
Date: 06-2012
DOI: 10.1016/J.CONB.2011.10.010
Abstract: Excitatory synaptic transmission is largely mediated by AMPA receptors (AMPARs) present at the postsynaptic density. Recent studies in single molecule tracking of AMPAR has revealed that extrasynaptic AMPARs are highly mobile and thus might serve as a readily available pool for their synaptic recruitment during synaptic plasticity events such as long-term potentiation (LTP). Because this hypothesis relies on the cell's ability to increase the number of diffusional traps or 'slots' at synapses during LTP, we will review a number of protein-protein interactions that might impact AMPARs lateral diffusion and thus potentially serve as slots. Recent studies have identified the interaction between the AMPAR-Stargazin complex and PSD-95 as the minimal components of the diffusional trapping slot. We will overview the molecular basis of this critical interaction, its activity-dependent regulation and its potential contribution to LTP.
Publisher: Rockefeller University Press
Date: 19-09-2016
Abstract: Munc18-1 and syntaxin-1A control SNARE-dependent neuroexocytosis and are organized in nanodomains on the plasma membrane of neurons and neurosecretory cells. Deciphering the intra- and intermolecular steps via which they prepare secretory vesicles (SVs) for fusion is key to understanding neuronal and hormonal communication. Here, we demonstrate that expression of a priming-deficient mutant lacking 17 residues of the domain 3a hinge-loop (Munc18-1Δ317-333) in PC12 cells engineered to knockdown Munc18-1/2 markedly prolonged SV docking. Single-molecule analysis revealed nonhomogeneous diffusion of Munc18-1 and syntaxin-1A in and out of partially overlapping nanodomains. Whereas Munc18-1WT mobility increased in response to stimulation, syntaxin-1A became less mobile. These Munc18-1 and syntaxin-1A diffusional switches were blocked by the expression of Munc18-1Δ317-333, suggesting that a conformational change in the Munc18-1 hinge-loop controls syntaxin-1A and subsequent SNARE complex assembly. Accordingly, syntaxin-1A confinement was prevented by expression of botulinum neurotoxin type E. The Munc18-1 domain 3a hinge-loop therefore controls syntaxin-1A engagement into SNARE complex formation during priming.
Publisher: Elsevier BV
Date: 06-2018
Publisher: Elsevier BV
Date: 07-2010
DOI: 10.1016/J.NEURON.2010.06.007
Abstract: The Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is critically required for the synaptic recruitment of AMPA-type glutamate receptors (AMPARs) during both development and plasticity. However, the underlying mechanism is unknown. Using single-particle tracking of AMPARs, we show that CaMKII activation and postsynaptic translocation induce the synaptic trapping of AMPARs diffusing in the membrane. AMPAR immobilization requires both phosphorylation of the auxiliary subunit Stargazin and its binding to PDZ domain scaffolds. It does not depend on the PDZ binding domain of GluA1 AMPAR subunit nor its phosphorylation at Ser831. Finally, CaMKII-dependent AMPAR immobilization regulates short-term plasticity. Thus, NMDA-dependent Ca(2+) influx in the post-synapse triggers a CaMKII- and Stargazin-dependent decrease in AMPAR diffusional exchange at synapses that controls synaptic function.
Publisher: Elsevier BV
Date: 2011
DOI: 10.1016/J.MCN.2010.08.014
Abstract: The amount of AMPARs at synapses is not a fixed number but varies according to different factors including synaptic development, activity and disease. Because the number of AMPARs sets the strength of synaptic transmission, their trafficking is subject to fine and tight regulation. In this review, we will describe the different steps taken by AMPARs in order to reach the synapse. We propose a three-step mechanism involving exocytosis at extra erisynaptic sites, lateral diffusion to synapses and a subsequent rate-limiting diffusional trapping step. We will describe how the different trafficking steps are regulated during synaptic plasticity or altered during neurodegenerative diseases such as Alzheimer's.
No related grants have been discovered for Daniel Choquet.