Relating ligand binding and activation gating in nicotinic acetylcholine receptors

Project Description

Nicotinic acetylcholine receptors (nAChRs) belong to the superfamily of cys-loop neurotransmitter-gated ion channels. They are expressed in different neuronal and non-neuronal cell types throughout the body, where they mediate fast synaptic cholinergic transmission. nAChR current responses are characterized by a rapid activation upon acetylcholine binding followed by a complex desensitization in the presence of the agonist. While the activation behavior is well understood, the desensitization is still a matter of debate. This project is intended to contribute to the understanding of the desensitization process in adult muscle-type nAChRs.

Because desensitized states are high-affinity states, which are electrically silent, the technical focus will be on the confocal patch-clamp fluorometry (cPCF), an approach combining electrophysiological patch-clamp techniques with confocal fluorescence microscopy. Using a fluorescently tagged acetylcholine analogue, this approach allows not only to control and to monitor receptor activation but also to simultaneously read out ligand binding. In contrast to pure electrophysiological approaches, state-dependent ligand binding can be monitored directly, thus contributing to a more complete picture of the desensitization process.

Title Year Authors Journal Links
Voltage-clamp and patch-clamp fluorometry: studying ion channels and transporters with light 2018 Kusch, J., and Zifarelli, G. The 2018 correlative microscopy techniques roadmap. Eds: Eggeling, C., Hogenboom, J.P., Schaap, IAT. J Physics D: Applied Physics More
Patch-clamp fluorometry: electrophysiology meets fluorescence 2014 Kusch, J., and Zifarelli, G. Biophys J More
The bile acid-sensitive ion channel (BASIC) is activated by alterations of its membrane environment 2014 Schmidt, A., Lenzig, P., Oslender-Bujotzek, A., Kusch, J., Dias Lucas, S., GrĂ¼nder, S., and Wiemuth, D. PLoS ONE More
Differential regulation by cyclic nucleotides of the CNGA4 and CNGB1b subunits in olfactory cyclic nucleotide-gated channels 2012 Nache, V., Zimmer, T., Wongsamitkul, N., Schmauder, R., Kusch, J., Reinhardt, L., Bonigk, W., Seifert, R., Biskup, C., Schwede, F. and Benndorf, K. Sci Signal More
Probability fluxes and transition paths in a Markovian model describing complex subunit cooperativity in HCN2 channels 2012 Benndorf, K., Kusch, J., and Schulz, E. PLoS Comput Biol More
How subunits cooperate in cAMP-induced activation of homotetrameric HCN2 channels 2011 Kusch, J., Thon, S., Schulz, E., Biskup, C., Nache, V., Zimmer, T., Seifert, R., Schwede, F., and Benndorf, K. Nat Chem Biol More
Interdependence of receptor activation and ligand binding in HCN2 pacemaker channels 2010 Kusch, J., Biskup, C., Thon, S., Schulz, E., Nache, V., Zimmer, T., Schwede, F. and Benndorf, K. Neuron More
Relating ligand binding to activation gating in CNGA2 channels 2007 Biskup, C., Kusch, J., Schulz, E., Nache, V., Schwede, F., Lehmann, F., Hagen, V. and Benndorf, K. Nature More