Poster Presentation 2014 International Biophysics Congress

Studying allosteric transitions of the pentameric ligand-gated ion channel GLIC using site-directed fluorescence (#434)

Anais Menny 1 2 3 , Marie Prevost 1 2 , Pierre-Jean Corringer 1 2
  1. Channel Receptors Unit, Pasteur Institute, Paris, France
  2. Unité Mixte de Recherche (UMR) 3571, Centre National de la Recherche Scientifique (CNRS), Paris, France
  3. University Pierre et Marie Curie (UPMC), Paris, France

Ligand gated ion channels are allosteric membrane proteins expressed at the post-synaptic membrane of synaptic junctions. They are responsible for the transduction of a chemical message, the binding of neurotransmitters or agonist, into an electrical signal at the membrane through the opening of their channel. A minimal 3 state allosteric model, comprising the resting, active and desensitized states, can describe their function. Several allosteric states have been crystalized for the prokaryotic homolog GLIC (Gloeobacter violaceus) but those structures were obtained on proteins extracted from membranes into detergent micelles and trapped into a crystal rising the question of “in what measure does those structures represent an actual allosteric state existing at the membrane”? In this project we develop a fluorescence technique allowing us to study the structural reorganisations underwent by channel receptors during allosteric transitions, in solution. By covalently binding a fluorophore to an engineered cysteine in the protein, we can generate “allosteric sensors” and follow structural movements of channel receptors when in presence of agonist.