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Nature. 2001 Mar 1;410(6824):41-9.

Synaptotagmin I functions as a calcium regulator of release probability.

Author information

1
Center for Basic Neuroscience, Department of Molecular Genetics, and Howard Hughes Medical Institute, The University of Texas Southwestern Medical Center, Dallas 75390-9111, USA.

Abstract

In all synapses, Ca2+ triggers neurotransmitter release to initiate signal transmission. Ca2+ presumably acts by activating synaptic Ca2+ sensors, but the nature of these sensors--which are the gatekeepers to neurotransmission--remains unclear. One of the candidate Ca2+ sensors in release is the synaptic Ca2+-binding protein synaptotagmin I. Here we have studied a point mutation in synaptotagmin I that causes a twofold decrease in overall Ca2+ affinity without inducing structural or conformational changes. When introduced by homologous recombination into the endogenous synaptotagmin I gene in mice, this point mutation decreases the Ca2+ sensitivity of neurotransmitter release twofold, but does not alter spontaneous release or the size of the readily releasable pool of neurotransmitters. Therefore, Ca2+ binding to synaptotagmin I participates in triggering neurotransmitter release at the synapse.

PMID:
11242035
DOI:
10.1038/35065004
[Indexed for MEDLINE]

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