ATTENUATED INFLUX OF CALCIUM-IONS AT NERVE-ENDINGS OF CSP AND SHIBIREMUTANT DROSOPHILA

Citation
Ja. Umbach et al., ATTENUATED INFLUX OF CALCIUM-IONS AT NERVE-ENDINGS OF CSP AND SHIBIREMUTANT DROSOPHILA, The Journal of neuroscience, 18(9), 1998, pp. 3233-3240
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Neurosciences
Journal title
ISSN journal
0270-6474
Volume
18
Issue
9
Year of publication
1998
Pages
3233 - 3240
Database
ISI
SICI code
0270-6474(1998)18:9<3233:AIOCAN>2.0.ZU;2-B
Abstract
Previous work has shown that cysteine-string proteins (csps) are synap tic vesicle proteins that are important for evoked neurotransmitter re lease at Drosophila neuromuscular junctions. Indirect evidence has imp licated csps in a regulatory link between synaptic vesicles and presyn aptic calcium (Ca) channels. In this report, we use Ca Crimson to moni tor stimulus-dependent changes of cytosolic Ca at motor nerve terminal s of csp mutant Drosophila. These mutants display temperature-sensitiv e (TS) paralysis and a presynaptic failure of evoked synaptic transmis sion. We show that this TS inhibition of neuromuscular transmission is correlated with a block of Ca ion entry at nerve endings of csp mutan ts. These data support the hypothesis that csps mediate a regulatory i nteraction between synaptic vesicles and presynaptic Ca channels. More over, these results predict that if one depletes nerve endings of syna ptic vesicles, one may see a reduction of presynaptic Ca ion entry. De fects of the dynamin gene in TS shibire mutant Drosophila interfere wi th synaptic vesicle recycling and lead to an activity-dependent deplet ion of these organelles. Our results show that Ca influx is blocked at nerve terminals of shibire mutant larvae at the same time that synapt ic transmission fails in these organisms. Thus, using two completely i ndependent Drosophila mutants, we demonstrate that synaptic vesicles a nd csps are vital for the function of presynaptic Ca channels.