Calcium in Color

Science Signaling  04 Oct 2011:
Vol. 4, Issue 193, pp. ec279
DOI: 10.1126/scisignal.4193ec279

Calcium indicators are widely used to detect intracellular signaling activity. A calcium indicator based on green fluorescent protein has been available for a decade. However, despite the success in engineering diverse fluorescent proteins, genetically encoded calcium imaging has remained limited to green. Zhao et al. developed a method to screen Escherichia coli colonies for calcium-dependent fluorescent changes and then used directed evolution to develop blue, red, and improved green indicators, as well as an emission ratiometric indicator. The indicators enabled multicolor calcium imaging in single cells, imaging of calcium dynamics, and imaging of neuronal activity in Caenorhabditis elegans.

Y. Zhao, S. Araki, J. Wu, T. Teramoto, Y.-F. Chang, M. Nakano, A. S. Abdelfattah, M. Fujiwara, T. Ishihara, T. Nagai, R. E. Campbell, An expanded palette of genetically encoded Ca2+ indicators. Science 333, 1888–1891 (2011). [Abstract] [Full Text]