Physiology of Ion Channels

Action potentials in neurons, the secretion of neurotransmitters and hormones, the contraction of skeletal muscles, and the heart beat are biological phenomena that are controlled by voltage-gated ion channels. These channels respond to changes in the membrane potential by opening and closing an ion permeation pathway across the membrane. This "gating" happens within milliseconds to seconds, and allows the selective passage pf specific ions (Na⁺, K⁺, Cl^-, Ca²⁺, or H⁺). We study the structure-function relationships and the physiology of these channels with electrophysiological and fluorometric methods.

Selected publications

Wobig, L., Wolfenstetter, T., Fechner, S., Bönigk, W., Körschen, H.G., Jikeli, J., Trötschel, C., Feederle, R., Kaupp, U.B., Seifert, R., and Berger, T.K. (2020). A family of hyperpolarization-activated channels selective for protons. Proc Acad Sci U S A, 202001214.

Molina-Obando, S., Vargas-Fique, J.F., Henning, M., Gur, B., Schladt, T.M., Akhtar, J., Berger, T.K., and Silies, M. (2019).ON selectivity in Drosophila vision is a multisynaptic process involving both glutamatergic and GABAergic inhibition. Elife 8, e49373.

Woeste, M.A., Stern, S., Raju, D.N., Grahn, E., Dittmann, D., Gutbrod, K., Dörmann, P., Hansen, J.N., Schonauer, S., Marx, C.E., Hamzeh, H., Körschen, H.G., Endepols, H., Sandhoff, R., Geyer, M., Berger, T.K., Bradke, F., and Wachten, D. (2019). Species-specific differences in nonlysosomal glucosylceramidase GBA2 function underlie locomotor dysfunction arising from loss-of-function mutations. J Biol Chem 294, 3853–3871.

Rennhack, A., Schiffer, C., Brenker, C., Fridman, D., Nitao, E. T., Cheng, Y. M., Tamburrino, L., Balbach, M., Stölting, G., Berger, T., Kierzek, M., Alvarez, L., Wachten, D., Zeng, X. H., Baldi, E., Publicover, S., Kaupp, U. B., and Strünker, T. (2018). "A novel cross-species inhibitor to study the function of CatSper Ca²⁺ channels in sperm." Br. J. Pharmacol. 175, 3144-3161.

Rennhack, A., Grahn, E., Kaupp, U.B. & Berger, T.K. (2017) “Photocontrol of the Hv1 proton channel” ACS Chem.Biol. 12, 2952-2957.

Berger, T.K., Fußhöller, D.M., Goodwin, N., Bönigk, W., Müller, A., Khesroshahi, N.D., Brenker, C., Wachten, D., Krause, E., Kaupp, U.B. & Strünker, T. (2017) "Post-translational cleavage of Hv1 in human sperm tunes pH- and voltage-dependent gating” J. Physiol. 595, 1533-1546

Fechner, S., Alvarez, L., Bönigk, W., Müller, A., Berger, T.K., Pascal, R., Trötschel, C., Poetsch, A., Stölting, G., Siegfried, K.R., Kremmer, E., Seifert, R. & Kaupp, U.B. (2015) "A K+-selective CNG channel orchestrates Ca2+ signalling in zebrafish sperm" eLife, e07624

Mony, L., Berger, T.K. & Isacoff, E.Y. (2015) "A specialized molecular motion opens the Hv1 voltage-gated proton channel" Nat. Struct. Mol. Biol. 22, 283-290

Berger, T.K. & Isacoff, E.Y. (2015) "Fluorescent Labeling for Patch-Clamp Fluorometry (PCF) Measurements of Real-Time Protein Motion in Ion Channels" Methods Mol. Biol. 1266, 93-106

Planert, H., Berger, T.K. & Silberberg, G. (2013) "Membrane properties of striatal direct and indirect pathway neurons in mouse and rat slices and their modulation of dopamine" PloS One 8, e57054

Berger, T.K. & Isacoff, E.Y. (2011) "The pore of the voltage gated proton channel" Neuron 72, 991-1000

Perin, R., Berger, T.K. & Markram, H. (2011) "A synaptic organizing principle for cortical neuronal groups" Proc. Natl. Acad. Sci. USA 108, 5419-5424

Berger, T.K., Silberberg, G., Perin, R. & Markram, H. (2010) "Brief bursts inhibit and correlate the pyramidal network" PLoS Biol. 8, e1000473

Berger, T.K., Perin, R., Silberberg, G. & Markram, H. (2009) "Frequency-dependent disynaptic inhibition in the pyramidal network: a ubiquitous pathway in the developing rat neocortex" J. Physiol. 587, 5411-5425

Wang, Y., Markram, H, Goldmann, P.H., Berger, T.K., Ma, J. & Goldmann-Rakic, P.S. (2006) "Heterogeneity in the pyramidal network of the medial prefrontal cortex" Nat. Neurosci. 9, 534-542

Funding

	Deutsche Forschungsgemeinschaft
	German-Israeli Foundation for Scientific Research and Development

Teaching

University of Bonn

Neuroscience Master Course:

"Principles of Neural Information Processing"

"Structure-Function Relationships of Ion Channels"

Member of "Bonner Forum für Biomedizin"