Multi-modal ion-transport function of potassium channelrhodopsins
- 1Nagoya Institute of Technology
Abstract
Light-gated K+ channelrhodopsins (KCRs) are recognized as an ideal neuronal silencing tool in optogenetics. KCRs contain functionally important residues for a light-driven H+ pump bacteriorhodopsin, but their roles have been unclear. Utilizing electrophysiological methods, we demonstrate that KCRs function as a light-driven H+ pump in the absence of K+. Transport experiments using pH electrodes further elucidated the function of the H+-pump, which operates even in the presence of K+. The hypothesis that the H+ pump exerts a blocking effect on K+ transport in KCRs has been postulated. Furthermore, we ascertained that there was conversion of KCRs from the H+ pump into the H+ channel by light, yet this conversion was never reversed. However, the addition of K+ resulted in the formation of the K+ channel. KCRs exhibit three distinct functional states, H+ pump, H+ channel, and K+ channel. These multifaceted functions are modulated by environmental ions and light.
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BibTeX
@misc{shimamura2026multimodal,
title = {{Multi-modal ion-transport function of potassium channelrhodopsins}},
author = {R. Shimamura and M. Kikuchi and T. Nakamura and S. Tajima and K. J. Fujimoto and M. Sugiura and J. Tabe and K. Minamisawa and R. Abe-Yoshizumi and T. Nishikino and S. Hososhima and T. Yanai and Y. Furutani and S. P. Tsunoda and H. Kandori},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.30.755824},
url = {https://www.biorxiv.org/content/10.64898/2026.09.30.755824v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Multi-modal ion-transport function of potassium channelrhodopsins
AU - R. Shimamura
AU - M. Kikuchi
AU - T. Nakamura
AU - S. Tajima
AU - K. J. Fujimoto
AU - M. Sugiura
AU - J. Tabe
AU - K. Minamisawa
AU - R. Abe-Yoshizumi
AU - T. Nishikino
AU - S. Hososhima
AU - T. Yanai
AU - Y. Furutani
AU - S. P. Tsunoda
AU - H. Kandori
PY - 2026
DA - 2026/09/30
PB - bioRxiv
DO - 10.64898/2026.09.30.755824
UR - https://www.biorxiv.org/content/10.64898/2026.09.30.755824v1
AB - Light-gated K+ channelrhodopsins (KCRs) are recognized as an ideal neuronal silencing tool in optogenetics. KCRs contain functionally important residues for a light-driven H+ pump bacteriorhodopsin, but their roles have been unclear. Utilizing electrophysiological methods, we demonstrate that KCRs function as a light-driven H+ pump in the absence of K+. Transport experiments using pH electrodes further elucidated the function of the H+-pump, which operates even in the presence of K+. The hypothesis that the H+ pump exerts a blocking effect on K+ transport in KCRs has been postulated. Furthermore, we ascertained that there was conversion of KCRs from the H+ pump into the H+ channel by light, yet this conversion was never reversed. However, the addition of K+ resulted in the formation of the K+ channel. KCRs exhibit three distinct functional states, H+ pump, H+ channel, and K+ channel. These multifaceted functions are modulated by environmental ions and light.
ER -