AequoScreen aequorin-encoding Plasmids for performing aequorin luminescent assay starting from non-aequorin cell lines

Calcium signaling and Aequorin Aequorin is a photoprotein originating from the jellyfish Aequorea Victoria (Inouye et al., Proc. Nat. Acad. Sci. USA 82, 3154-3158, 1985; Prasher et al., Biochem. Biophys. Res. Commun. 126 :1259-1268, 1985). The apo-enzyme (apoaequorin) is a 21 kD protein, which requires a hydrophobic prosthetic group, coelenterazine, to be converted to aequorin, the active form of the enzyme. This enzyme possesses 3 calcium binding sites which control its activity. Upon calcium binding, aequorin oxidizes coelenterazine into coelenteramide with the production of CO2 and emission of light. The consumption of aequorin is proportional to the calcium concentration within a physiological range (50 nM to 50 μM) (Brini et al., J. Biol. Chem. 270: 9896-9903, 1995; Rizzuto et al., Biochem. Biophys. Res. Commun. 126: 1259-1268, 1995). Therefore, measurement of the light emitted upon oxidation of coelenterazine is a reliable tool for measurement of intracellular calcium flux and furthermore generates results comparable to those obtained with traditional fluorescent dyes (Brini et al., J. Biol. Chem. 270: 9896-9903, 1995).