Nagel, Georg and Szellas, Tanjef and Huhn, Wolfram and Kateriya, Suneel and Adeishvili, Nona and Berthold, Peter and Ollig, Doris and Hegemann, Peter and Bamberg, Ernst (2003) Channelrhodopsin-2, a directly light-gated cation-selective membrane channel. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 100 (24). pp. 13940-13945. ISSN 0027-8424
Full text not available from this repository.Abstract
Microbial-type rhodopsins are found in archaea, prokaryotes, and eukaryotes. Some of them represent membrane ion transport proteins such as bacteriorhodopsin, a light-driven proton pump, or channelrhodopsin-1 (ChR1), a recently identified light-gated proton channel from the green alga Chlamydomonas reinhardtii. ChR1 and ChR2, a related microbial-type rhodopsin from C. reinhardtii, were shown to be involved in generation of photocurrents of this green alga. We demonstrate by functional expression, both in oocytes of Xenopus laevis and mammalian cells, that ChR2 is a directly light-switched cation-selective ion channel. This channel opens rapidly after absorption of a photon to generate a large permeability for monovalent and divalent cations. ChR2 desensitizes in continuous light to a smaller steady-state conductance. Recovery from desensitization is accelerated by extracellular H+ and negative membrane potential, whereas closing of the ChR2 ion channel is decelerated by intracellular H+. ChR2 is expressed mainly in C reinhardtii under low-light conditions, suggesting involvement in photoreception in dark-adapted cells. The predicted seven-transmembrane a helices of ChR2 are characteristic for G protein-coupled receptors but reflect a different motif for a cation-selective ion channel. Finally, we demonstrate that ChR2 may be used to depolarize small or large cells, simply by illumination.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | GREEN-ALGA CHLAMYDOMONAS; SENSORY RHODOPSIN-II; PHOTOPHOBIC RESPONSES; VOLTAGE-DEPENDENCE; BACTERIORHODOPSIN; REINHARDTII; PHOTOTAXIS; CURRENTS; INSIGHTS; CALCIUM; voltage clamp; patch clamp; light sensitive; Chlamydomonas reinhardtii; Xenopus laevis oocyte |
| Subjects: | 500 Science > 540 Chemistry & allied sciences 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie > Lehrstuhl für Biochemie I |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 27 Jul 2021 11:01 |
| Last Modified: | 27 Jul 2021 11:01 |
| URI: | https://pred.uni-regensburg.de/id/eprint/38398 |
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