Research Projects

Team Project Summary

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Cytoskeleton and membrane interplay in synaptic organization and transmission (Anna Brachet).

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Chemical Biology and Protein Engineering (Matthieu Sainlos)

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Impact of auxiliary proteins on AMPAR transport, trafficking and physiology (Françoise Coussen).

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nanoscale excitatory synaptic physiology (Eric Hosy).

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Contribution of AMPAR surface trafficking to Short and long term synaptic plasticity (Daniel Choquet)

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Synapse dysfunction in neurodevelopmental disorders (Eric Hosy, Daniel Choquet)

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Partnerships

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Expertise

Super Resolution Microscopy

Slice physiology

Chemical biology, Protein Engineering

Biochemistry

News

Co-organization and coactivation of AMPAR, NMDAR, and mGluR

Nanoscale co-organization and coactivation of AMPAR, NMDAR, and mGluR at excitatory synapses.

The nanoscale co-organization of neurotransmitter receptors facing presynaptic release sites is a fundamental determinant of their coactivation and of synaptic physiology. At excitatory synapses, how endogenous AMPARs, NMDARs, and mGluRs are co-organized inside the synapse and their respective activation during glutamate release are still unclear. Combining single-molecule super resolution microscopy, electrophysiology, and modeling, we determined the average quantity of each glutamate receptor type, their nanoscale organization, and their respective activation. We observed that NMDARs form a unique cluster mainly at the center of the PSD, while AMPARs segregate in clusters surrounding the NMDARs.mGluR5 presents a different organization and is homogenously dispersed at the synaptic surface. From these results, we build a model predicting the synaptic transmission properties of a unitary synapse, allowing better understanding of synaptic physiology.

Authors: Julia Goncalves, Tomas M. Bartol, Côme Camus, Florian Levet, Ana Paula Menegolla,Terrence J. Sejnowski, Jean-Baptiste Sibarita, Michel Vivaudou, Daniel Choquet and Eric Hosy

- Publication in PNAS, June 8, 2020 https://doi.org/10.1073/pnas.1922563117
- Contact: Eric Hosy

AMPA receptor nanoscale dynamic organization and synaptic plasticities

Review on “AMPA receptor nanoscale dynamic organization and synaptic plasticities” in Current Opinion in Neurobiology 2020

The emergence of new imaging techniques and molecular tools has refreshed our understanding of the principles of synaptic transmission and plasticity. Superresolution imaging and biosensors for measuring enzymatic activities in live neurons or neurotransmitter levels in the synaptic cleft are giving us an unprecedented integrated and nanoscale view on synaptic function. Excitatory synapses are now conceptualized as organized in subdomains, enriched with specific scaffolding proteins and glutamate receptors, molecularly organized with respect to the pre-synaptic source of glutamate.

This new vision of basic synaptic transmission changes our understanding of the molecular modifications which sustain synaptic plasticities. Long-term potentiation can no longer be explained simply by an increase in receptor content at the synapse. We review here the latest data on the role of nanoscale and dynamic organization of AMPA type glutamate receptors on synaptic transmission at both basal state and during short and long-term plasticities.

 Current Opinion in Neurobiology - Volume 63, August 2020, Pages 137-145 https://doi.org/10.1016/j.conb.2020.04.003
 Contacts: Daniel Choquet and Eric Hosy

A discrete presynaptic vesicle cycle for neuromodulator receptors - Neuron, December 2019

A major function of GPCRs is to inhibit presynaptic neurotransmitter release, requiring ligand-activated receptors to couple locally to effectors at terminals. The current understanding of how this is achieved is through receptor immobilization on the terminal surface. Here, we show that opioid peptide receptors, GPCRs that mediate highly sensitive presynaptic inhibition, are instead dynamic in axons. Opioid receptors diffuse rapidly throughout the axon surface and internalize after ligand-induced activation specifically at presynaptic terminals. We delineate a parallel regulated endocytic cycle for GPCRs operating at the presynapse, separately from the synaptic vesicle cycle, which clears activated receptors from the surface of terminals and locally reinserts them to maintain the diffusible surface pool. We propose an alternate strategy for achieving local control of presynaptic effectors that, opposite to using receptor immobilization and enforced proximity, is based on lateral mobility of receptors and leverages the inherent allostery of GPCR-effector coupling.

Damien Jullié, Miriam Stoeber, Jean-Baptiste Sibarita, Hanna L. Zieger, Thomas M. Bartol, Seksiri Arttamangkul, Terrence J. Sejnowski, Eric Hosy, and Mark von Zastrow

- Neuron. 2019 Dec 5 - doi: 10.1016/j.neuron.2019.11.016.
- Contact: Eric Hosy

Multicolor Spectrin labeling (ML Jobin)

This is a rat hippocampal neuron in culture stained with a series of markers

Nature Neuroscience Review - Choquet D., Sainlos M. and Sibarita J.B.

We review the latest developments for labelling and functionalizing proteins with small localization and functionalized reporters. We present how these molecular tools are combined with the development of a wide variety of imaging methods that break either the diffraction barrier or the tissue penetration depth limits. We put these developments in perspective to emphasize how they will enable step changes in our understanding of the brain.

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BRAIN_2030 «Grand Programme de Recherche» de l'université de Bordeaux

The BRAIN_2030 project (“Bordeaux Region Aquitaine Initiative for the future of Neurosciences”), submitted by Bordeaux Neurocampus within the “GPR - Major Research Program” of the University of Bordeaux, and headed by Daniel Choquet, has just been approved. It is one of the 7 projects selected out of the 15 submitted in June 2020.

A dialogue phase is planned to validate the final budget that will be allocated for the period 2021-2025. Additional funding for an additional period will be granted after an interim evaluation in 2025.

The project starts in September 2021.

+ Find more details on the Université of Bordeaux (UB) and the Bordeaux Neurocampus (BN) websites.

Access the hidden side of neuronal proteins through the expansion of the genetic code

Progress in biological imaging is intrinsically linked to advances in labeling methods. The explosion in the development of high-resolution and super-resolution imaging calls for new approaches to label targets with small probes. These should allow to faithfully report the localization of the target within the imaging resolution – typically nowadays a few nanometers - and allow access to any epitope of the target, in the native cellular and tissue environment. We report here the development of a complete labeling and imaging pipeline using genetic code expansion and non-canonical amino acids in neurons that allows to fluorescently label masked epitopes in target transmembrane proteins in live neurons, both in dissociated culture and organotypic brain slices. This allows us to image the differential localization of two AMPA receptor (AMPAR) auxiliary subunits of the transmembrane AMPAR regulatory protein family in complex with their partner with a variety of methods including widefield, confocal, and dSTORM super-resolution microscopy.

Authors: Diogo Bessa-Neto & Gerti Beliu, Alexander Kuhlemann, Valeria Pecoraro, Sören Doose, Natacha Retailleau, Nicolas Chevrier, David Perrais, Markus Sauer & Daniel Choquet

Bioorthogonal labeling of transmembrane proteins with non-canonical amino acids unveils masked epitopes in live neurons.
Nature Communications (November 2021) DOI: 10.1038/s41467-021-27025-w

Contact: Daniel Choquet

+ Cf. INSB website (French) here
+ Cf. the press release on the University of Würzburg website here

Selected Publications

Choquet D., Sainlos M. and Sibarita J.B.

Advanced imaging and labelling methods to decipher brain cell organization and function Nature reviews Neuroscience (2021)
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Tomohisa Hosokawa, Pin-Wu Liu, Qixu Cai, Joana S. Ferreira, Florian Levet, Corey Butler, Jean-Baptiste Sibarita, Daniel Choquet, Laurent Groc, Eric Hosy, Mingjie Zhang and Yasunori Hayashi 

CaMKII activation persistently segregates postsynaptic proteins via liquid phase separation Nature Neuroscience (2021)
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Diogo Bessa-Neto, Gerti Beliu, Alexander Kuhlemann, Valeria Pecoraro, Sören Doose, Natacha Retailleau, Nicolas Chevrier, David Perrais, Markus Sauer & Daniel Choquet

Bioorthogonal labeling of transmembrane proteins with non-canonical amino acids unveils masked epitopes in live neurons Nature Communications (2021)
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Laurent Groc & Daniel Choquet

Linking glutamate receptor movements and synapse function Science (2020)
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Julia Goncalves, Tomas M Bartol, Côme Camus, Florian Levet, Ana Paula Menegolla, Terrence J Sejnowski, Jean-Baptiste Sibarita, Michel Vivaudou, Daniel Choquet, Eric Hosy

Nanoscale co-organization and coactivation of AMPAR, NMDAR, and mGluR at excitatory synapses Proc Natl Acad Sci U S A (2020)
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Tiago Campelo, Elisabete Augusto, Nicolas Chenouard, Aron de Miranda, Vladimir Kouskoff, Come Camus, Daniel Choquet, Frédéric Gambino

AMPAR-Dependent Synaptic Plasticity Initiates Cortical Remapping and Adaptive Behaviors during Sensory Experience Cell Report (2020)
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Florelle Domart, Peter Cloetens, Stéphane Roudeau, Asuncion Carmona, Emeline Verdier, Daniel Choquet, Richard Ortega

Correlating STED and synchrotron XRF nano-imaging unveils cosegregation of metals and cytoskeleton proteins in dendrites eLife (2020)
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Humeau, Y. and Choquet, D.

The next generation of approaches to investigate the link between synaptic plasticity and learning. Nature Neuroscience (2019)
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Charlotte Rimbault, Kashyap Maruthi, Christelle Breillat, Camille Genuer, Sara Crespillo, Virginia Puente-Muñoz, Ingrid Chamma, Isabel Gauthereau, Ségolène Antoine, Coraline Thibaut, Fabienne Wong Jun Tai, Benjamin Dartigues, Dolors Grillo-Bosch, Stéphane Claverol, Christel Poujol, Daniel Choquet, Cameron D Mackereth, Matthieu Sainlos

Engineering selective competitors for the discrimination of highly conserved protein-protein interaction modules Nature Communication (2019)
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Emilie Hangen, Fabrice P Cordelières, Jennifer D Petersen, Daniel Choquet, Françoise Coussen

Neuronal Activity and Intracellular Calcium Levels Regulate Intracellular Transport of Newly Synthesized AMPAR Cell Report (2018)
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Penn, A.C., Zhang, C.L., Georges, F., Royer, L., Breillat, C., Hosy, E., Petersen, J.D., Humeau, Y., and Choquet, D.

Hippocampal LTP and contextual learning require surface diffusion of AMPA receptors Nature (2017)
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Audrey Constals, Andrew C Penn, Benjamin Compans, Estelle Toulmé, Amandine Phillipat, Sébastien Marais, Natacha Retailleau, Anne-Sophie Hafner, Françoise Coussen, Eric Hosy, Daniel Choquet

Glutamate-induced AMPA receptor desensitization increases their mobility and modulates short-term plasticity through unbinding from Stargazin Neuron (2015)
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Anne-Sophie Hafner, Andrew C Penn, Dolors Grillo-Bosch, Natacha Retailleau, Christel Poujol, Amandine Philippat, Françoise Coussen, Matthieu Sainlos, Patricio Opazo, Daniel Choquet

Lengthening of the Stargazin Cytoplasmic Tail Increases Synaptic Transmission by Promoting Interaction to Deeper Domains of PSD-95 Neuron (2015)
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Deepak Nair, Eric Hosy, Jennifer D Petersen, Audrey Constals, Gregory Giannone, Daniel Choquet, Jean-Baptiste Sibarita

Super-resolution imaging reveals that AMPA receptors inside synapses are dynamically organized in nanodomains regulated by PSD95 Journal of Neuroscience (2013)
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Heine, M., Groc, L., Frischknecht, R., Beique, J.C., Lounis, B., Rumbaugh, G., Huganir, R.L., Cognet, L., and Choquet, D.

Surface mobility of postsynaptic AMPARs tunes synaptic transmission Science (2008)
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Aren J Borgdorff and Daniel Choquet

Regulation of AMPA receptor lateral movements Nature (2002)
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« Alumni & Guests »

Former group members, follow-up last known position

• Aren borgdorff - 1997-2000, Industry
• Arnauld Sergé - 1997-2001, Assistant professor Marseille
• Marianne Renner - 2004-2006, Professor, Paris
• Caroline Dequidt - 2004-2007, Industry
• Cécile Bats - 2004-2007, Post-doc, London
• Martin Heine - 2003-2007, Junior group leader, Magdeburg
• Enrica Petrini - 2005-2008, Post-doc, Genoa
• Cezar Tigaret - 2006-2009, Lecturer, Bristol
• Helge Ewers - 2007-2009, Group leader, Berlin
• Arnaud Frouin - 2007-2010, Labmanager, NYC
• Leandro Royer - 2009-2012, Post-doc, Boston
• Patricio Opazo - 2008-2013, Group leader, Brisbane
• Jary Delgado - 2009-2013, Post-doc, Chicago
• Deepak Nair - 2009-2013, Group leader, Bengalor
• Damien Jullié - 2009-2013, Post-doc, San Francisco
• Audrey Constal - 2010-2013, Teacher
• Axel Athane - 2011-2013, Industry
• Dolors Grillo, 2011-2013, Post-doc, Spain
• Anne-Sophie Hafner - 2010-2014, Post-doc, Frankfurt
• Isabelle Gautherau - 2012-2014, Industry
• Amandine Philippat - 2013-2015, Industry
• Andrew Penn - 2010-2015, Junior group leader, Sussex
• Hongyu Zhang - 2010-2015, Post-doc, University of Bergen
• Estelle Toulme - 2013-2015, Post-doc, Berlin
• Jennifer Petersen - 2009-2016, Post-doc, NIH
• Yulia Krapivkina - 2013-2016, Industry
• Ngoc Van Thi Nhu - 2013-2016, Engineer, Montpellier
• Emilie Hangen - 2014-2017
• Ségolène Antoine - 2015-2017, French Industry
• Sara Crespillo - 2015-2017, Post-doc, Cambridge
• Célia Michel - 2014-2017, French Industry
• Benjamin Compans - 2014-2018, Post-doc, London
• Lucile Pret - 2018, Engineer, London
• Julia Goncalves – 2015 – 2018, Engineer, Bordeaux Neurocampus
• Murielle Fevre - 2017-2018
• Camille Genuer - 2017-2018, Engineer, French Industry
• Carla Montecinos - 2013-2018, post-doc Bordeaux
• Charlotte Rimbault – 2014-2019, Post-doc, Copenhagen
• Magalie Martineau – 2015-2019, Post-doc, Paris
• Léa Claverie – 2015 - 2019, UK
• Florelle Domart - 2016-2019, Post-doc Goettingen
• David Perrais - 2011-2020, Group Leader
• Sylvia Sposini - 2018-2020, Post-doc, Bordeaux
• Lou Bouit - 2018-2020, Engineer, Bordeaux 
• Côme Camus - 2018-2021, Medical Intern, Bordeaux 
• Caroline Bonnet - 2017-2021
• Inès Gonzalès-Calvo - 2019-2021
• Valeria Pecoraro - 2019-2021

Guests

• Raffaella Adami, Pisa - January, June 2001
• Andres Villu Maricq, Utah - November 2003
• Radhika Reddy, Worley lab - June 2003
• Michael Ehlers, Duke University - March, September 2006
• Renatto Frischknecht, Gundelfinger lab - April 2006, September 2006
• Laura Andreae, Fine lab - April 2006, November 2006
• Anna Carbone, Plested Lab - January, April 2012
• Beulah Leitch, Otago University - October 2013
• Andrew Plested, FMP Berlin - October 2015, February 2016
• Nikolaj Riis Christensen, Copenhagen University - June-December 2017
• Anne Brunet, Stanford University - April-July 2019
• Pin Wu Liu, Kyoto University Graduate School of Medicine - January 2020
• Boram Lee, Johannes W. Hell UCDavis - January-June 2020

Jobs

Engineer in super-resolution microscopy

Within the team "Dynamic Organization of Synapses", the engineer will be tasked to conduct super-resolution imaging experiments based on single molecule detection, STED, expansion microscopy, etc. for the study of the nanoscale organization of synaptic proteins.

He/she will be placed under the direct responsibility of the group leader and will work closely with the other researchers in the team to provide support to all of the team's projects requiring super-resolution approaches. He/she will also work in partnership with the other teams in the unit using these approaches as well as with the Bordeaux Imaging Center imaging platform and will participate in the team's internal and external collaborative projects. He/she will be required to work in international collaborations in this area. He/she will be responsible for the development of new sample preparation and image acquisition protocols. He/she will participate in the methodological and instrumental developments in super-resolution imaging carried out within the team. It will also process and analyze the corresponding data. He/she will provide advice and support to team members on these technologies. He/she will conduct projects, analyze, render and trace the results.

PhD position

The dendritic spine is a small protrusive structure that is made of a head and a narrow neck emerging from the dendritic shaft. This structure is crucial for neuronal physiology as it is where the postsynaptic compartment of most excitatory synapses is localized and its peculiar shape allows for specific micro-compartmentalization of neuronal signaling. Spine morphology is very plastic; spine head and neck sizes correlate almost perfectly with synaptic strength and spines grow or shrink during synaptic potentiation or depression, respectively. Importantly, the molecular composition and the correlated morphology of spines are critical for synaptic function. Mechano-sensing is emerging as a key mechanism regulating neuronal functions during physiological processes, including neuronal development and synaptic transmission. Despite the fact that they probably involve adhesion and cytoskeleton proteins, the molecular mechanisms underlying neuronal mechano-sensing remain unknown. The overarching objective of this PhD project addresses this precise fundamental question.

In collaboration with the group of Gregory Giannone (IINS), different methods to deform spines by applying external mechanical forces will be used. Their impacts on spine shape, mechanical stability and synaptic transmission will be studied by a combination of molecular tools, electrophysiology and state of the art imaging methods, including super-resolution microscopy but also FRET-based force sensors imaging.

As a first molecular target for mechanical regulation/transduction of dendritic spines, the PhD student will study the role of a major class of cytoskeletal protein called β spectrins. Spectrins have actin-binding domains at their ends and various membrane-interacting sites along their length. Spectrin's functions are best characterized in erythrocytes, where the 2D membrane-bound actin-spectrin network maintains the biconcave cell shape and provides mechanical support. Spectrins are also present in other cells and are especially important for the nervous system. In fact, several pathogenic variants have been recently described in central nervous system diseases including developmental delay and autistic features. The emergence of super-resolution microscopy in the past years uncovered the peculiar organization adopted by actin and β spectrins in neurons at the nanoscopic level. A ring-like actin-spectrin network structure appears in axons with 180–190nm periodicity. A similar periodic pattern in patches of dendrites and in spines has been described and is under detailed characterization in the team. The team already demonstrated that spectrin removal leads to a drastic reduction of dendritic spine number and prevents dendritic spine shape changes during synaptic plasticity. Interestingly, β spectrin is composed of specific domains unfolding upon mechanical forces, as demonstrated for proteins involved in mechano-sensing and mechano-transduction. This led to the hypothesis that the ring-like actin-spectrin network may have a mechano-protective or even a mechano-transduction role during synaptic plasticity.

The PhD student will now investigate the impact of spectrin perturbations (mutants CRISPR/CAS9 KO) on dendritic spine mechanical and functional behavior with the experimental approaches described above.