Project B2

Gating and ion transport dynamics in channelrhodopsin

Principal Investigator: Prof. Dr. Peter Hegemann (HU)

Within project B2 we aim at understanding the dynamics of the H-bonding network and the process of H+-conduction through this network during the open states of Channelrhodopsin. Based on the recently published structure, we will study function and dynamics of the certain ChR-epitopes by electrophysiological methods addressing the central gate, inner gate, active site, and other regions of the protein. In addition, we will study the photochemical back reaction of the conducting state since it is essential for adaptation and steady-state currents under high light conditions. Based on these studies we will extend the kinetic model and produce (and investigate) ChR-variants with high selectivity for Ca2+ or K+.

Publications 2013 - 2017

AzimiHashemi, N., Erbguth, K., Vogt, A., Riemensperger, T., Rauch, E., Woodmansee, D., Nagpal, J., Brauner, M., Sheves, M., Fiala, A., Kattner, L., Trauner, D., Hegemann, P., Gottschalk, A., and Liewald, J.F. (2014). Synthetic retinal analogues modify the spectral and kinetic characteristics of microbial rhodopsin optogenetic tools. Nature Communications 5, 5810.

Berndt, A., Lee, S.Y., Wietek, J., Ramakrishnan, C., Steinberg, E.E., Rashid, A.J., Kim, H., Park, S., Santoro, A., Frankland, P.W., Iyer, S.M., Pak, S., Ahrlund-Richter, S., Delp, S.L., Malenka, R.C., Josselyn, S.A., Carlen, M., Hegemann, P., and Deisseroth, K. (2016). Structural foundations of optogenetics: Determinants of channelrhodopsin ion selectivity. Proc. Natl. Acad. Sci. U.S.A. 113, 822-829.

Ernst, O.P., Lodowski, D.T., Elstner, M., Hegemann, P., Brown, L.S., and Kandori, H. (2014). Microbial and Animal Rhodopsins: Structures, Functions, and Molecular Mechanisms. Chemical Reviews 114, 126-163.

Grimm, C., Vierock, J., Hegemann, P., and Wietek, J. (2017). Whole-cell Patch-clamp Recordings for Electrophysiological Determination of Ion Selectivity in Channelrhodopsins. Journal of Visualized Experiments 55497.

Krause, B.S., Grimm, C., Kaufmann, J.C.D., Schneider, F., Sakmar, T.P., Bartl, F.J., and Hegemann, P. (2017). Complex Photochemistry within the Green-Absorbing Channelrhodopsin ReaChR. Biophysical Journal 112, 1166-1175.

Kuhne, J., Eisenhauer, K., Ritter, E., Hegemann, P., Gerwert, K., and Bartl, F. (2015). Early Formation of the Ion-Conducting Pore in Channelrhodopsin-2. Angewandte Chemie International Edition 54, 4953-4957.

Richter, F., Scheib, U.S., Mehlhorn, J., Schubert, R., Wietek, J., Gernetzki, O., Hegemann, P., Mathes, T., and Moeglich, A. (2015). Upgrading a microplate reader for photobiology and all-optical experiments. Photochemical & Photobiological Sciences 14, 270-279.

Rost, B.R., Schneider, F., Grauel, M.K., Wozny, C., G Bentz, C., Blessing, A., Rosenmund, T., Jentsch, T.J., Schmitz, D., Hegemann, P., et al. (2015). Optogenetic acidification of synaptic vesicles and lysosomes. Nature Neuroscience 18, 1845-1852.

Scheib, U., Stehfest, K., Gee, C.E., Korschen, H.G., Fudim, R., Oertner, T.G., and Hegemann, P. (2015). The rhodopsin-guanylyl cyclase of the aquatic fungus Blastocladiella emersonii enables fast optical control of cGMP signaling. Science Signaling 8, rs8.

Schneider, F., Gradmann, D., and Hegemann, P. (2013). Ion Selectivity and Competition in Channelrhodopsins. Biophysical Journal 105, 91-100.

Schneider, F., Grimm, C., and Hegemann, P. (2015). Biophysics of Channelrhodopsin. Annual Review of Biophysics 44, 167-186.

Vogt, A., Guo, Y., Tsunoda, S.P., Kateriya, S., Elstner, M., and Hegemann, P. (2015). Conversion of a light-driven proton pump into a light-gated ion channel. Scientific Reports 5, 16450.

Vogt, A., Wietek, J., and Hegemann, P. (2013). Gloeobacter Rhodopsin, Limitation of Proton Pumping at High Electrochemical Load. Biophysical Journal 105, 2055-2063.

Wietek, J., Beltramo, R., Scanziani, M., Hegemann, P., Oertner, T.G., and Simon Wiegert, J. (2015). An improved chloride-conducting channelrhodopsin for light-induced inhibition of neuronal activity in vivo. Scientific Reports 5, 14807.

Wietek, J., Broser, M., Krause, B.S., and Hegemann, P. (2016). Identification of a Natural Green Light Absorbing Chloride Conducting Channelrhodopsin from Proteomonas sulcata. J. Biol. Chem. 291, 4121-4127.

Wietek, J., Wiegert, J.S., Adeishvili, N., Schneider, F., Watanabe, H., Tsunoda, S.P., Vogt, A., Elstner, M., Oertner, T.G., and Hegemann, P. (2014). Conversion of channelrhodopsin into a light-gated chloride channel. Science 344, 409-412. [Link to news section.]