Max Planck Institute for Dynamics and Self-Organization -- Department for Nonlinear Dynamics and Network Dynamics Group
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Tuesday, 04.06.2013 17 c.t.

Characterization and engineering of photoreceptors for optogenetic applications

by Prof. Dr. Georg Nagel
from Julius-von-Sachs-Institut für Biowissenschaften, Lehrstuhl für Botanik I, Würzburg

Contact person: André Fiala (Schwann-Schleiden Forschungszentrum)


Ludwig Prandtl lecture hall


Photoreceptors from archaea, bacteria, and green algae were molecularly identified in recent years. We could show that some of them are ideal tools to manipulate animal cells by illumination. The Channelrhodopsins from the unicellular green alga C. reinhardtii are Light-gated cation channels which allow fast light-induced depolarization1,2 of the plasma membrane. Mutations led to a slower photocycle and therefore to Channelrhodopsins with higher light sensitivity. Neuronal expression of Channelrhodopsin-2 (ChR2) yields Light-induced action potentials and Light-manipulated behaviour3 in C. elegans. The Light-activated chloride pump halorhodopsin (HR) from the archaeum Natronomonas pharaonis hyperpolarizes the plasma membrane and therefore allows Light-induced silencing of neurons4. These two antagonistic rhodopsins may even be expressed in the same cell and still specifically be light-activated with 460 nm for ChR2 and 580 nm for HR. We heterologously express Photoactivated Adenylyl Cyclases (PAC) from Euglena gracilis (5,6) or Beggiatoa spec. (7), flavoproteins which quickly elevate cytoplasmic cyclic AMP by illumination with blue light in cultured cells and in living animals or plants. References: 1: Nagel G., D. Ollig, M. Fuhrmann, S. Kateriya, A.M. Musti, E. Bamberg, P. Hegemann (2002). Channelrhodopsin-1: a light-gated proton channel in green algae. Science 296: 2395-2398 2: Nagel, G, T. Szellas, W. Huhn, S. Kateriya, N. Adeishvili, P. Berthold, D. Ollig, P. Hegemann, E. Bamberg. (2003) Channelrhodopsin-2, a directly Light-gated Cation-selective Membrane Channel. Proc Natl Acad Sci U.S.A. 100:13940-13945 3: Nagel, G., M. Brauner, J.F. Liewald, N. Adeishvili, E. Bamberg, A. Gottschalk (2005) Light-activation of Channelrhodopsin-2 in excitable cells of Caenorhabditis elegans triggers rapid behavioral responses. Current Biology 15(24):2279-84. 4: Zhang F., L.-P. Wang, M. Brauner, J.F. Liewald, K. Kay, N. Watzke, P.G. Wood, E. Bamberg, G. Nagel, A. Gottschalk, and K. Deisseroth (2007) Multimodal fast optical interrogation of neural circuits. Nature 446:633-639 5: Schröder-Lang, S., M. Schwärzel, R. Seifert, T. Strünker, S. Kateriya, J. Looser, M. Watanabe, U. B. Kaupp, P. Hegemann, G. Nagel (2007) Fast manipulation of cellular cAMP level by light in vivo. Nat Methods 4(1):39-42 6: Looser J, Schröder-Lang S, Hegemann P, Nagel G. (2009) Mechanistic insights in light-induced cAMP production by photoactivated adenylyl cyclase alpha (PACalpha). Biol Chem. 390(11):1105-11 7: Stierl M, Stumpf P, Udwari D, Gueta R, Hagedorn R, Losi A, Gärtner W, Petereit L, Efetova M, Schwarzel M, Oertner TG, Nagel G, Hegemann P. (2011) Light-modulation of cellular cAMP by a small bacterial photoactivated adenylyl cyclase, bPAC, of the soil bacterium Beggiatoa. J Biol Chem. 286(2):1181-8

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