A dual-purpose real-time indicator and transcriptional integrator for calcium detection in living cells

Calcium is a ubiquitous second messenger in eukaryotes, correlated with neuronal activity and T-cell activation among other processes. Real-time calcium indicators such as GCaMP have recently been complemented by newer calcium integrators that convert transient calcium activity into stable gene expression. Here we introduce LuCID, a dual-purpose real-time calcium indicator and transcriptional calcium integrator which combines the benefits of both calcium detection technologies. We show that the calcium-dependent split luciferase component of LuCID provides real-time bioluminescence readout of calcium dynamics in cells, while the GI/FKF1 split GAL4 component of LuCID converts bioluminescence into stable gene expression. We also show that LuCID modular design enables it to also be used for dual-purpose detection of other cellular events such as protein-protein interactions. LuCID should facilitate the study of cell populations and circuits that utilize calcium for signaling.

An ionic liquid composed of purely functional sensing molecules: a colorimetrically calcium responsive ionic liquid

A new unique ionic liquid consisting of two purely functional sensing molecules, an anionic calcium ionophore and a cationic dye, was developed for the first time, and highly sensitive calcium detection was achieved.