Aequorin

Aequorin is a protein found in certain jellyfish that can produce light when it reacts with calcium ions in cells. Scientists use it as a biological tool to measure calcium levels inside living cells, which are important for many processes like nerve signaling and muscle contraction. When calcium binds to aequorin, it causes a chemical reaction that emits a blue glow. This glow can be measured with specialized devices, allowing researchers to monitor cellular activity in real-time. Aequorin has been valuable in studying how cells communicate and respond to different stimuli.