The novel family of genetically encoded calcium indicators, named ‘Twitch’ sensors, fulfill the majority of criteria and represent a major improvement over most existing indicators. The name of the indicators originates from the fact that their calcium sensor is derived from troponin C, a calcium-binding protein found in skeletal and cardiac muscle (but not neurons) that regulates muscle twitching.
Wilms, C., & Häusser, M. (n.d.). Twitching towards the ideal calcium sensor. Nature Methods., 11(2), 139-140.
Calcium is an exquisitely versatile signaling molecule, determining both cell differentiation and death as well as triggering neurotransmission and regulating synaptic plasticity. Consequently, determining the spatial and temporal dynamics of intracellular calcium concentration, [Ca2+], is crucial not only in cell biology but also for understanding immune physiology and brain function. Unsurprisingly, measuring [Ca2+] dynamics is one of the main uses of fluorescence microscopy and has spurred the development of new indicators for many decades