Platymonas subcordiformis Calcium-translocating Channelrhodopsin 2.0 (PsCatCh2.0)

Platymonas subcordiformis Calcium-translocating Channelrhodopsin 2.0 (PsCatCh2.0) is an engineered microbial opsin utilized in optogenetic gene therapy to restore vision in patients with advanced retinal degeneration (Kleinlogel et al., 2011). It is a light-gated cation channel derived from the green alga Platymonas subcordiformis, specifically optimized for high light sensitivity and rapid kinetics to match the physiological requirements of visual processing (University of Bern, 2020). The retinal binding pocket is the critical functional domain where the cofactor all-trans-retinal binds via a Schiff base; upon absorbing a photon, the retinal isomerizes, causing the channel to open and depolarize the retinal ganglion cell (RGC) in which it is expressed. This mechanism allows RGCs to bypass lost or damaged photoreceptors and transmit visual information directly to the brain (Bery et al., 2021). PsCatCh2.0 is designed to function under ambient light conditions, addressing a major limitation of earlier optogenetic tools that required potentially harmful levels of light intensity for activation.

Other names

PsChR-L132C variantPlatymonas subcordiformis channelrhodopsin 2.0CatCh2.0Engineered PsChR

Light-induced isomerization of the chromophore all-trans-retinal within the binding pocket triggers a conformational change that opens the channel pore, allowing cation influx and subsequent depolarization of the retinal ganglion cell.