An expanded palette of genetically encoded Ca²⁺ indicators

Science. 2011 Sep 30;333(6051):1888-91. doi: 10.1126/science.1208592. Epub 2011 Sep 8.


Engineered fluorescent protein (FP) chimeras that modulate their fluorescence in response to changes in calcium ion (Ca(2+)) concentration are powerful tools for visualizing intracellular signaling activity. However, despite a decade of availability, the palette of single FP-based Ca(2+) indicators has remained limited to a single green hue. We have expanded this palette by developing blue, improved green, and red intensiometric indicators, as well as an emission ratiometric indicator with an 11,000% ratio change. This series enables improved single-color Ca(2+) imaging in neurons and transgenic Caenorhabditis elegans. In HeLa cells, Ca(2+) was imaged in three subcellular compartments, and, in conjunction with a cyan FP-yellow FP-based indicator, Ca(2+) and adenosine 5'-triphosphate were simultaneously imaged. This palette of indicators paints the way to a colorful new era of Ca(2+) imaging.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Animals, Genetically Modified
  • Caenorhabditis elegans
  • Calcium / analysis*
  • Calcium Signaling*
  • Directed Molecular Evolution*
  • Fluorescence
  • Fluorescence Resonance Energy Transfer
  • Green Fluorescent Proteins / chemistry*
  • Green Fluorescent Proteins / genetics
  • HeLa Cells
  • Humans
  • Luminescent Proteins / chemistry*
  • Luminescent Proteins / genetics
  • Molecular Sequence Data
  • Neurons / metabolism
  • Protein Engineering*
  • Rats
  • Recombinant Fusion Proteins / chemistry*
  • Spectrometry, Fluorescence
  • Transfection


  • Luminescent Proteins
  • Recombinant Fusion Proteins
  • Green Fluorescent Proteins
  • Adenosine Triphosphate
  • Calcium

Associated data

  • GENBANK/JN258409
  • GENBANK/JN258410
  • GENBANK/JN258411
  • GENBANK/JN258412
  • GENBANK/JN258413
  • GENBANK/JN258414
  • GENBANK/JN258415