photoproteins are excellent reporter systems because they don’t have virtually background signal. aequorin is the most well-known photoprotein. three improved engineered photoproteins photina, i-photina and c-photina, were also recently developed and optimized for generation of ca2+ mobilization assays precisely. the total light emission is greater than aequorin and their reaction kinetics is a...

Aequorin is a photoprotein which emits light in response to changes in free calcium concentration. When aequorin was microinjected into plasmodia of Physarum polycephalum, light emission varied in synchrony with the motile oscillations of the organisms. Therefore, movement is correlated which changes in the concentration of free calcium.

Aequorin is a Ca2+ sensitive photoprotein suitable to measure intracellular Ca2+ transients in mammalian cells. Thanks to recombinant cDNAs expression, aequorin can be specifically targeted to various subcellular compartments, thus allowing an accurate measurement of Ca2+ uptake and release of different intracellular organelles. Here, we describe how to use this probe to measure cytosolic Ca2+ ...

tages and disadvantages, have been empelyed. The bioluminescent photoprotein, aequorin, can measuTe fast Ca '+ transients, but its sensitivity is poor for measuring resting [Ca'']i (1,25): A Ca"-sensitive microelectrode can detect resting [Ca-']i levels, but the measuTements aTe subject to various degrees of error due to impalernent damage (5,18,21). The nullpoint titration method using arsenaz...

Ca2+-regulated photoproteins are members of the EF-hand calcium-binding protein family. The addition of Ca2+ produces a blue bioluminescence by triggering a decarboxylation reaction of protein-bound hydroperoxycoelenterazine to form the product, coelenteramide, in an excited state. Based on the spatial structures of aequorin and several obelins, we have postulated mechanisms for the Ca2+ trigge...

The calcium-triggered photoprotein aequorin has been used as a sensitive indicator of cytoplasmic free calcium in cells of relatively large size. We describe here several novel modifications to the technique that make it possible to detect resting levels of free calcium in single mammalian oocytes, fibroblasts and granulosa cells. Concentrations of free calcium as low as 1 X 10(-7) M have been ...

A fusion protein has been expressed from the relevant genes in mammalian cells consisting of the photoprotein aequorin and an anti-4-hydroxy-3-nitrophenacetyl antibody gene. This chimeric antibody has allowed the development of a sensitive luminescent immunoassay. Initially the cDNA of the photoprotein aequorin from Aequorea victoria was cloned and expressed in Escherichia coli. The gene was ex...

  Photoproteins are excellent reporter systems because they don’t have virtually background signal. Aequorin is the most well-known photoprotein. Three improved engineered photoproteins photina, i-photina and c-photina, were also recently developed and optimized for generation of Ca2+ mobilization assays precisely. The total light emission is greater than aequorin and their reacti...