Aequorinbased

Aequorinbased refers to the use of aequorin, a calcium-activated photoprotein originally isolated from the jellyfish Aequorea victoria, as a reporter or sensor for intracellular calcium. In the presence of calcium, aequorin binds the substrate coelenterazine to form a luminescent complex that emits blue light with a peak near 465 nm. The resulting luminescence is proportional to calcium concentration over a physiological range, enabling real-time monitoring of calcium dynamics in living cells and tissues.

Applications of aequorinbased systems span cellular biology, neuroscience, physiology, and drug discovery. They are used as reporters to quantify Ca2+ fluctuations during neuronal activity, muscle contraction, and embryonic development. In vitro and in vivo assays employ aequorin to measure calcium signaling, often in high-throughput formats where luminescence readouts provide low background and good dynamic range. Targeted aequorin constructs can be directed to specific cellular compartments to study localized calcium signals.

Advantages of aequorinbased indicators include the absence of external excitation light, which reduces autofluorescence and phototoxicity, and the ability to measure calcium signals over extended periods with continuous or repeated measurements. Limitations include dependence on the delivery and stability of the coelenterazine substrate, signal decay as aequorin is consumed, and a blue emission that can be attenuated by tissues and may complicate multiplexing with other reporters. Variants and optimizations have focused on improving brightness, calcium sensitivity, and subcellular targeting, as well as adapting aequorin-based readouts for different experimental contexts.