Moreau Team

Team Leader: Christophe Moreau (CNRS, DR2)

INTRODUCTION

Among the protein components of biological membranes, the team is mainly interested in two families of membrane proteins: 1) transmembrane receptors and 2) ion channels. The main methods used are electrophysiological techniques (two-electrode voltage-clamp on xenopus oocytes), protein engineering using PCR and biochemical techniques (purification).

1) The G-Protein Coupled Receptors (GPCRs) are the main transmembrane receptors studied. They are involved in a very large number of physiological processes and constitute the largest family of membrane proteins encoded in the human genome with more than 800 genes. We have co-developed the ‘Ion Channel-Coupled Receptor’ (ICCR) technology by linking G Protein Coupled Receptors (GPCRs) to different ion channels. Applications are envisaged as a novel proximal assay of GPCR activity, and as protein biosensors compatible with microelectronic devices. We have demonstrated that the binding of ligands (agonists or antagonists) to fused GPCRs is translated into an electrical signal by the ion channel. This technology offers a number of advantages: real-time measurement, no labelling, signal proportional to ligand concentration, independence from intracellular signalling pathways, interfaceability with micro- and nano-electronic devices.
We used ICCRs to identify a cross-regulatory mechanism between cholesterol and oxytocin in the oxytocin receptor (OXTR).
Olfactory GPCRs have also been fused as part of the ERC NANOZ-ONIC project in partnership with Professor Park T.H. and Professor Hong S. of Seoul National University. The aim is to create electronic noses for non-invasive in vitro diagnostic applications.

2) Various ion channels are also being studied.
The involvement of an astrocytic ion channel in Alzheimer’s disease is being studied at the molecular level from two angles: i) by heterologous expression in xenopus oocytes and electrophysiological characterisation using voltage-gated microelectrodes; ii) by structural approach using cryo-electron microscopy.
Insect olfactory receptors are also ion channels. In collaboration with Jérémie Topin from the Université Nice Côte d’Azur, we have demonstrated ligand entry and binding in the Orco co-receptor.

Methods:
– Two-electrode voltage-clamp(HiClamp(R) robots, MCS)
– In vitro synthesis of mRNA
– Microinjection of mRNA into xenopus oocytes
– Insect cell culture
– Site directed mutagenesis/protein engineering

Key Words:

Structure-function relationships of receptors ; Structure-function relationships of channel ; Protein design and engineering ; Methodological developments

Ion Channel-Coupled Receptor (ICCR), G Protein Coupled Receptors (GPCR), Olfacory receptors, Ion channel, Kir6.2, electrophysiology, double-microelectrodes, voltage-clamp, patch-clamp, HiClamp, Xenopus oocytes

Selected articles:

https://www.webofscience.com/wos/author/record/148275

(* corresponding author ; ° equal contribution)

  • Pacalon J°, Audic G°, Magnat J, Philip M, Golebiowski J, Moreau CJ*, Topin J*. Elucidation of the structural basis for ligand binding and translocation in conserved insect odorant receptor co-receptors. Nat Commun. 2023 ; 14 : 8182.
    Highlights : CNRS Biologie
  • Moreau CJ*, Audic G, Lemel L, García-Fernández MD, Nieścierowicz K. Interactions of cholesterol molecules with GPCRs in different states: A comparative analysis of GPCRs’ structures. Biochim Biophys Acta Biomembr. 2023 ; 1865 : 184100.
  • Lemel L°, Nieścierowicz K°, García-Fernández MD°, Darré L, Durroux T, Busnelli M, Pezet M, Rébeillé F, Jouhet J, Mouillac B, Domene C, Chini B, Cherezov V, Moreau CJ*. The ligand-bound state of a G protein-coupled receptor stabilizes the interaction of functional cholesterol molecules. J. Lipid Res. 2021 ; 62 : 10059.
    Highlights : ASBMB today
  • Principalli MA, Lemel L, Rongier A, Godet A-C, Langer K, Revilloud J, Darré L, Domene C, Vivaudou M, Moreau CJ*. Functional Mapping of the N-terminal Arginine Cluster and C-terminal Acidic Residues of Kir6.2 channel Fused to a G Protein-Coupled Receptor. BBA Biomembranes 2017 ; 1859:2144.
  • Moreau CJ*, Revilloud J, Caro LN, Dupuis JP, Trouchet A, Estrada-Mondragón A, Nieścierowicz K, Vivaudou M. Tuning the allosteric regulation of artificial muscarinic and dopaminergic ligand-gated potassium channels by protein engineering of G protein-coupled receptors. Sci. Rep. 2017 ; 7:41154.
  • Moreau CJ*, Niescierowicz K, Caro L, Revilloud J, Vivaudou M*. Ion channel reporter for monitoring the activity of engineered GPCRs. Methods Enzymol. 2015 ; 556:425-54.
  • Hassaine G, Deluz C, Grasso L, Wyss R, Tol MB, Hovius R, Graff A, Stahlberg H, Tomizaki T, Desmyter A, Moreau C, Li X-D, Poitevin F, Vogel H, Nury H. X-ray structure of the mouse serotonin 5-HT3 receptor. Nature. 2014 ; 512:276-81.
  • Niescierowicz K, Caro L, Cherezov V, Vivaudou M, Moreau CJ*. Functional assay for T4 lysozyme-engineered G Protein-Coupled Receptors with an ion channel reporter. Structure. 2014 ; 22:149-55.
  • Caro LN, Moreau CJ, Estrada-Mondragón A, Ernst OP, Vivaudou M. Engineering of an artificial light-modulated potassium channel. PLoS One. 2012 ; 7:e43766.
  • Caro LN, Moreau CJ, Revilloud J, Vivaudou M. β(2)-Adrenergic Ion-Channel Coupled Receptors as Conformational Motion Detectors. PLoS One. 2011, 6:e18226.
  • Moreau C.J*., Dupuis JP., Revilloud J., Arumugam K. and Vivaudou M*. Electrical biosensors engineered by assembly of a potassium channel with G-protein-coupled receptors. Nature Nanotechnology 2008, 3 : 620-625.

Fundings:

Current:

  • ANR eSPRi (2022-2026)
  • ANR Bac4Nose (2024-2028)

Past:

  • ERC CoG NANOZ-ONIC 682286 (2015-2022)
  • CNRS MITI (2019-2020)
  • ANSES (2016-2019)