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The kinetic mechanisms of fast-decay red-fluorescent genetically encoded calcium indicators.

Kerruth, S; Coates, C; Dürst, CD; Oertner, TG; Török, K (2019) The kinetic mechanisms of fast-decay red-fluorescent genetically encoded calcium indicators. J Biol Chem, 294 (11). pp. 3934-3946. ISSN 1083-351X https://doi.org/10.1074/jbc.RA118.004543
SGUL Authors: Torok, Katalin

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Abstract

Genetically encoded calcium indicators (GECIs) are useful reporters of cell-signaling, neuronal, and network activities. We have generated novel fast variants and investigated the kinetic mechanisms of two recently developed red-fluorescent GECIs (RGECIs), mApple-based jRGECO1a and mRuby-based jRCaMP1a. In the formation of fluorescent jRGECO1a and jRCaMP1a complexes, calcium binding is followed by rate-limiting isomerization. However, fluorescence decay of calcium-bound jRGECO1a follows a different pathway from its formation: dissociation of calcium occurs first, followed by the peptide, similarly to GCaMP-s. In contrast, fluorescence decay of calcium-bound jRCaMP1a occurs by the reversal of the on-pathway: peptide dissociation is followed by calcium. The mechanistic differences explain the generally slower off-kinetics of jRCaMP1a-type indicators compared with GCaMP-s and jRGECO1a-type GECI: the fluorescence decay rate of f-RCaMP1 was 21 s−1, compared with 109 s−1 for f-RGECO1 and f-RGECO2 (37 °C). Thus, the CaM–peptide interface is an important determinant of the kinetic responses of GECIs; however, the topology of the structural link to the fluorescent protein demonstrably affects the internal dynamics of the CaM–peptide complex. In the dendrites of hippocampal CA3 neurons, f-RGECO1 indicates calcium elevation in response to a 100 action potential train in a linear fashion, making the probe particularly useful for monitoring large-amplitude, fast signals, e.g. those in dendrites, muscle cells, and immune cells.

Item Type: Article
Additional Information: © 2019 Kerruth et al. Author's Choice—Final version open access under the terms of the Creative Commons CC-BY license (http://creativecommons.org/licenses/by/4.0).
Keywords: biosensor, calcium, calcium imaging, fluorescence, kinetics, biosensor, calcium, calcium imaging, fluorescence, kinetics, 06 Biological Sciences, 11 Medical And Health Sciences, 03 Chemical Sciences, Biochemistry & Molecular Biology
SGUL Research Institute / Research Centre: Academic Structure > Molecular and Clinical Sciences Research Institute (MCS)
Journal or Publication Title: J Biol Chem
ISSN: 1083-351X
Language: eng
Dates:
DateEvent
15 March 2019Published
16 January 2019Published Online
16 January 2019Accepted
Publisher License: Creative Commons: Attribution 4.0
Projects:
Project IDFunderFunder ID
BB/M02556X/1Biotechnology and Biological Sciences Research Councilhttp://dx.doi.org/10.13039/501100000268
PubMed ID: 30651353
Go to PubMed abstract
URI: http://openaccess.sgul.ac.uk/id/eprint/110567
Publisher's version: https://doi.org/10.1074/jbc.RA118.004543

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