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Nat Commun. 2013;4:2170. doi: 10.1038/ncomms3170.

Fast GCaMPs for improved tracking of neuronal activity.

Author information

1
Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA.
2
Neuroscience Institute, Princeton University, Princeton, New Jersey 08544, USA.
#
Contributed equally

Abstract

The use of genetically encodable calcium indicator proteins to monitor neuronal activity is hampered by slow response times and a narrow Ca(2+)-sensitive range. Here we identify three performance-limiting features of GCaMP3, a popular genetically encodable calcium indicator protein. First, we find that affinity is regulated by the calmodulin domain's Ca(2+)-chelating residues. Second, we find that off-responses to Ca(2+) are rate-limited by dissociation of the RS20 domain from calmodulin's hydrophobic pocket. Third, we find that on-responses are limited by fast binding to the N-lobe at high Ca(2+) and by slow binding to the C-lobe at lower Ca(2+). We develop Fast-GCaMPs, which have up to 20-fold accelerated off-responses and show that they have a 200-fold range of K(D), allowing coexpression of multiple variants to span an expanded range of Ca(2+) concentrations. Finally, we show that Fast-GCaMPs track natural song in Drosophila auditory neurons and generate rapid responses in mammalian neurons, supporting the utility of our approach.

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PMID:
23863808
PMCID:
PMC3824390
DOI:
10.1038/ncomms3170
[Indexed for MEDLINE]
Free PMC Article
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