Functional characteristics of animal opsins as optical control tools.

Abstract

In optogenetics, not only channelrhodopsins but also animal opsins have been used as efficient optical control tools. Animal opsins have been extensively investigated using various spectroscopic, biochemical, electrophysiological, and biophysical research techniques for more than 150 years. Based on the accumulated insights, I introduce functional characteristics of animal opsins, and discuss their potentials as optical control tools to expand our understanding of biological phenomena. In particular, I summarize advantages of “invertebrate-type” opsins as optical control tools, because they can function without supply of “cis-” retinal isomers and they can be activated and inactivated by stimulation of different color of light.