Visible light excited ratiometric-GECIs for long-term in-cellulo monitoring of calcium signals
Jia Li, Liuqing Wang, Yilan Chen, Yang Yang, Jin Liu, Kai Liu, Yi‐Tsang Lee, Ningjia He, Yubin Zhou, Youjun Wang
Abstract
Genetically Encoded Calcium Indicators (GECIs) are powerful molecular tools for monitoring calcium (Ca2+) signaling in the cytosol and organellar compartments. However, currently available ratiometric indicators that allow measurements of resting Ca2+ levels have limitations in long-term Ca2+ imaging. They either are ultraviolet (UV)-excited ones with strong photo-toxicity, or have poor performance. To overcome this hurdle, we developed a set of visible light excited ratiometric-GECIs (VR-GECIs) based on existing mono-colored GECIs. With performance comparable to their corresponding mono-color prototypes, this set of VR-GECIs enables long-term measurements of intra-cellular or intra-organellar Ca2+ signals. Using these VR-GECIs together with a newly developed off-line analysis tool, we achieved long-term measurements of Ca2+ homeostasis of moving or dividing cells. Our tools may find broad applications in decoding Ca2+-modulated physiological or pathological processes.