Referenced in: none

Automatically associated channels: BKβ , Slo1

Title: Ultra light-sensitive and fast neuronal activation with the Ca²+-permeable channelrhodopsin CatCh.

Authors: Sonja Kleinlogel, Katrin Feldbauer, Robert E Dempski, Heike Fotis, Phillip G Wood, Christian Bamann, Ernst Bamberg

Journal, date & volume: Nat. Neurosci., 2011 Apr , 14, 513-8

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/21399632

Abstract
The light-gated cation channel channelrhodopsin-2 (ChR2) has rapidly become an important tool in neuroscience, and its use is being considered in therapeutic interventions. Although wild-type and known variant ChR2s are able to drive light-activated spike trains, their use in potential clinical applications is limited by either low light sensitivity or slow channel kinetics. We present a new variant, calcium translocating channelrhodopsin (CatCh), which mediates an accelerated response time and a voltage response that is ~70-fold more light sensitive than that of wild-type ChR2. CatCh's superior properties stem from its enhanced Ca²(+) permeability. An increase in [Ca²(+)](i) elevates the internal surface potential, facilitating activation of voltage-gated Na(+) channels and indirectly increasing light sensitivity. Repolarization following light-stimulation is markedly accelerated by Ca²(+)-dependent BK channel activation. Our results demonstrate a previously unknown principle: shifting permeability from monovalent to divalent cations to increase sensitivity without compromising fast kinetics of neuronal activation. This paves the way for clinical use of light-gated channels.