Far-red fluorescent genetically encoded calcium ion indicators
Genetically encoded calcium ion (Ca<sup>2+</sup>) indicators (GECIs) are widely-used molecular tools for functional imaging of Ca<sup>2+</sup> dynamics and neuronal activities with single-cell resolution. Here we report the design and development of two far-red fluorescent GECIs, FR-GECO1a and FR-GECO1c, based on the monomeric far-red fluorescent proteins mKelly1 and mKelly2. FR-GECOs have excitation and emission maxima at ~596 nm and ~644 nm, respectively, display large responses to Ca<sup>2+</sup> in vitro (ΔF/F<sub>0</sub> = 6 for FR-GECO1a, 18 for FR-GECO1c), are bright under both one-photon and two-photon illumination, and have high affinities (apparent K<sub>d</sub> = 29 nM for FR-GECO1a, 83 nM for FR-GECO1c) for Ca<sup>2+</sup>. FR-GECOs offer sensitive and fast detection of single action potentials in neurons, and enable in vivo all-optical manipulation and measurement of cellular activities in combination with optogenetic actuators.
Authors
- Takuya Terai (ORCID: https://orcid.org/0000-0002-3425-3589)
- Eric R. Schreiter (ORCID: https://orcid.org/0000-0002-2864-7469)
- Rochelin Dalangin (ORCID: https://orcid.org/0000-0002-1914-507X)
- Yitong Qi
- Ahmed S. Abdelfattah (ORCID: https://orcid.org/0000-0001-8131-1772)
- Sean G. Megason (ORCID: https://orcid.org/0000-0002-9330-2934)
- Kaspar Podgorski (ORCID: https://orcid.org/0000-0002-0374-2005)
- Ronak Patel (ORCID: https://orcid.org/0000-0002-6945-6466)
- Marie-Ève Paquet (ORCID: https://orcid.org/0000-0001-6982-4970)
- Jiahui Wu (ORCID: https://orcid.org/0000-0003-2406-6728)
- Abhi Aggarwal (ORCID: https://orcid.org/0000-0002-6336-566X)
- Adam E. Cohen (ORCID: https://orcid.org/0000-0002-8699-2404)
- J. Hasseman (ORCID: https://orcid.org/0000-0002-0096-7321)
- Robert E. Campbell (ORCID: https://orcid.org/0000-0003-0604-092X)
- Alison G. Tebo (ORCID: https://orcid.org/0000-0003-0788-5617)
- Mikhail Drobizhev (ORCID: https://orcid.org/0000-0001-9072-1300)
- Daniel Reep
- Rosana S. Molina (ORCID: https://orcid.org/0000-0001-7891-2462)
- Bill Jia (ORCID: https://orcid.org/0000-0002-1138-3217)
- Y Zhao (ORCID: https://orcid.org/0000-0002-1788-7969)
- Thomas E. Hughes
- Jihong Zheng (ORCID: https://orcid.org/0000-0002-1247-6087)
- Yi Shen (ORCID: https://orcid.org/0000-0003-4117-0279)
- Kenryo Sakoi
Institutions
- Allen Institute for Brain Science (US)
- Howard Hughes Medical Institute (US)
- Harvard University (US)
- University of Alberta (CA)
- University of Calgary (CA)
- Janelia Research Campus (US)
- Montana State University (US)
- University of Massachusetts Amherst (US)
- Montana Molecular (United States) (US)
- Cermaq (Canada) (CA)
- Allen Institute (US)
- Center for Systems Biology (US)
- National Research Council Canada (CA)
- Université Laval (CA)
- Allen Institute for Neural Dynamics (US)
- Libin Cardiovascular Institute of Alberta (CA)
- The University of Tokyo (JP)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-04-07
- DOI
- https://doi.org/10.1038/s41467-025-58485-z
- Citations
- 12
- Primary Topic
- Advanced biosensing and bioanalysis techniques
- Type
- article
- Field-Weighted Citation Impact
- 9.67
Funders
- Howard Hughes Medical Institute
- University of Alberta
- National Institutes of Health
- Canadian Institutes of Health Research
- Natural Sciences and Engineering Research Council of Canada
- Japan Society for the Promotion of Science
- National Institute of Neurological Disorders and Stroke