2026 — Peter Hegemann

Evidence: 39 • authority: 88

The past, present and future of light-gated ion channels and optogenetics. The discovery of the mechanisms underlying light-gated ion channels called channelrhodospins and the subsequent development of optogenetics illustrates how breakthroughs in science and technology can span multiple levels of scientific inquiry. Our knowledge of how channelrhodopsins work emerged from research at the microscopic level that investigated the structure and function of algal proteins. Optogenetics, on the other hand, exploits the power of channelrhodospins and similar proteins to investigate phenomena at the supra-macroscopic level, notably the neural circuits involved in animal behavior that may be releva…

Evidence: 20 • authority: 88

Conversion of a light-driven proton pump into a light-gated ion channel. Abstract Interest in microbial rhodopsins with ion pumping activity has been revitalized in the context of optogenetics, where light-driven ion pumps are used for cell hyperpolarization and voltage sensing. We identified an opsin-encoding gene (CsR) in the genome of the arctic alga Coccomyxa subellipsoidea C-169 that can produce large photocurrents in Xenopus oocytes. We used this property to analyze the function of individual residues in proton pumping. Modification of the highly conserved proton shuttling residue R83 or its interaction partner Y57 strongly reduced pumping power. Moreover, this mutation converted CsR…

Evidence: 20 • authority: 80

The Diversity of Light-Driven Ion Pumps and their Conversion into Ion Channels

Evidence: 20 • authority: 88

Channelrhodopsins: directly light-gated cation channels. Phototaxis and photophobic responses of green algae are mediated by rhodopsins with microbial type chromophores, i.e. all-trans-retinal in the ground state. The green alga Chlamydomonas reinhardtii was recently completely sequenced and the EST (expressed sequence tag) database was made public. We and others detected overlapping partial cDNA sequences that encode two proteins which we termed channelopsins (Chops). The N-terminal half of chop1 (∼300 of 712 amino acids) comprises hypothetical seven-transmembrane segments with sequence similarity to the proton pump bacteriorhodopsin and the chloride pump halorhodopsin. Even though the ove…

Evidence: — • authority: 50