Pump-like channelrhodopsins: Not just bridging the gap between ion pumps and ion channels

Channelrhodopsins are microbial rhodopsins that work as light-gated ion channels. Their importance has become increasingly recognized due to their ability to control the membrane potential of specific cells in a light-dependent manner. This technology, termed optogenetics, has revolu-tionized neuroscience, and numerous channelrhodopsin vari-ants have been isolated or engineered to expand the utility of optogenetics. Pump-like channelrhodopsins (PLCRs), one of the recently discovered channelrhodopsin subfamilies, have attracted broad attention due to their high sequence similarity to ion-pumping rhodopsins and their distinct properties, such as high light sensitivity and ion selectivity. In this review, we summarize the current understanding of the structure-function relationships of PLCRs and discuss the challenges and op-portunities of channelrhodopsin research.

Automated summary

Channelrhodopsins are microbial rhodopsins that function as light-gated ion channels to control specific cells' membrane potential in a light-dependent manner. Optogenetics, the technology utilizing this, has revolutionized neuroscience, and various channelrhodopsin variants have been discovered or engineered for expanding its applications. Pump-like channelrhodopsins (PLCRs), a recent subfamily with high sequence similarity to ion-pumping rhodopsins, have gained attention for their unique properties such as high light sensitivity and ion selectivity. This review summarizes the current understanding of PLCRs' structure-function relationships and discusses the challenges and opportunities of channelrhodopsin research.