Distinct roles for two synaptotagmin isoforms in synchronous and asynchronous transmitter release at zebrafish neuromuscular junction.
An obligatory role for the calcium sensor synaptotagmins in stimulus-coupled release of neurotransmitter is well established, but a role for synaptotagmin isoform involvement in asynchronous release remains conjecture. We show, at the zebrafish neuromuscular synapse, that two separate synaptotagmins underlie these processes. Specifically, knockdown of synaptotagmin 2 (syt2) reduces synchronous release, whereas knockdown of synaptotagmin 7 (syt7) reduces the asynchronous component of release. The zebrafish neuromuscular junction is unique in having a very small quantal content and a high release probability under conditions of either low-frequency stimulation or high-frequency augmentation. Through these features, we further determined that during the height of shared synchronous and asynchronous transmission these two modes compete for the same release sites.
Wen
Hua
H
Vollum Institute, Oregon Health and Sciences University, Portland, OR 97239, USA.
Linhoff
Michael W
MW
McGinley
Matthew J
MJ
Li
Geng-Lin
GL
Corson
Glen M
GM
Mandel
Gail
G
Brehm
Paul
P
D000818:Animals; D008969:Molecular Sequence Data; D009469:Neuromuscular Junction / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D009435:Synaptic Transmission; D050857:Synaptotagmins / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015027:Zebrafish / Q000378:metabolism*
D020033:Protein Isoforms; D050857:Synaptotagmins