Emerging Concepts in Ion Channel Biophysics

Emerging Concepts in Ion Channel Biophysics

Poster Abstracts

38-POS Board 38 Unravelling the Structure-function Relationship of the Glyr Veerle Lemmens 1,2 , Waldemar Schrimpf 3 , Bert Brône 1 , Jochen Meier 4 , Don Lamb 3 , Johan Hofkens 2 , Jelle Hendrix 1,2 1 Bioimaging and Physiology group, Biomedical research institute (BIOMED), Hasselt University, Diepenbeek, Belgium; 2 Molecular Imaging and Photonics division, Chemistry Department, KU Leuven, Belgium; 3 Fluorescence Applications in Biology group, Chemistry Department, Ludwig-Maximilians-Universität, Munich, Germany; 4 Zoologisches Institut, Technische Universität Braunschweig, Germany The glycine receptor (GlyR) is a protein involved in neuron communication. Upon binding of glycine it transports chloride ions, thereby fine-tuning neuron activity. Dysfunction of the GlyR is linked to neurological disorders including hyperekplexia, autism and temporal lobe epilepsy. Furthermore, the alpha 3 type GlyR is a promising target to treat pain, but more fundamental insights on receptor structure and function are needed. As it consists of five subunits, different combinations of subunits lead to receptors with different properties. The diversity between GlyR isoforms is further increased by alternative splicing and RNA editing. We want to characterize the different α3 GlyR splice variants (K/L) and investigate the precise mechanism of GlyR channel gating. To determine the GlyR a3K/L pentamer composition at the ensemble level in live cells, we recently developed a new fluorescence fluctuation imaging method (‘raster spectral image correlation spectroscopy’, RSICS). To corroborate the pentamer composition we employ single-molecule sensitive fluorescence imaging. To provide insights into the dynamic channel structure, we employ single-molecule Förster resonance energy transfer, by labeling the receptor on cells using amber suppression technology. Our final goal is to combine fluorescence microscopy and electrophysiology measurements on a single setup, to link GlyR activity directly with structural properties (e.g. cellular distribution, quaternary composition and overall structure) in real-time and at the single-cell or even single- receptor level. We hope that information from our research can be translated into the development of isoform-specific ligands.

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