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Cysteine string protein‐α is essential for the high calcium sensitivity of exocytosis in a vertebrate synapse
Author(s) -
Ruiz R.,
Casañas J. J.,
Südhof T. C.,
Tabares L.
Publication year - 2008
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2008.06301.x
Subject(s) - exocytosis , neurotransmission , synapse , synaptic vesicle , microbiology and biotechnology , extracellular , biology , cysteine , neuroscience , chemistry , secretion , biochemistry , vesicle , receptor , enzyme , membrane
Cysteine string protein (CSPα) is a synaptic vesicle protein present in most central and peripheral nervous system synapses. Previous studies demonstrated that the deletion of CSPα results in postnatal sensorial and motor impairment and premature lethality. To understand the participation of CSPα in neural function in vertebrates, we have studied the properties of synaptic transmission of motor terminals in wild‐type and CSPα knockout mice. Our results demonstrate that, in the absence of CSPα, fast Ca 2+ ‐triggered release was not affected at postnatal day (P)14 but was dramatically reduced at P18 and P30 without a change in release kinetics. Although mutant terminals also exhibited a reduction in functional vesicle pool size by P30, further analysis showed that neurotransmission could be ‘rescued’ by high extracellular [Ca 2+ ] or by the presence of a phorbol ester, suggesting that an impairment in the fusion machinery, or in vesicle recycling, was not the primary cause of the dysfunction of this synapse. The specific shift to the right of the Ca 2+ dependence of synchronous release, and the lineal dependence of secretion on extracellular [Ca 2+ ] in mutant terminals after P18, suggests that CSPα is indispensable for a normal Ca 2+ sensitivity of exocytosis in vertebrate mature synapses.