PT  - JOURNAL ARTICLE
AU  - Zhao Xuan
AU  - Laura Manning
AU  - Jessica Nelson
AU  - Janet E. Richmond
AU  - Daniel Colón-Ramos
AU  - Kang Shen
AU  - Peri T. Kurshan
TI  - Clarinet (CLA-1), a novel active zone protein required for synaptic vesicle clustering and release
AID  - 10.1101/145789
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 145789
4099  - http://biorxiv.org/content/early/2017/06/03/145789.short
4100  - http://biorxiv.org/content/early/2017/06/03/145789.full
AB  - Active zone proteins cluster synaptic vesicles at presynaptic terminals and coordinate their release. In forward genetic screens we isolated a novel C. elegans active zone gene, clarinet (cla-1). cla-1 mutants exhibit defects in synaptic vesicle clustering, reduced spontaneous neurotransmitter release, increased synaptic depression and reduced synapse number. Ultrastructurally, cla-1 mutants have fewer synaptic vesicles adjacent to the dense projection and an increased number of docked vesicles. Cla-1 encodes 3 isoforms containing common C-terminal PDZ and C2 domains with homology to vertebrate active zone proteins Piccolo and RIM. The short isoform localizes exclusively to the active zone while a longer ~9000 amino acid isoform colocalizes with synaptic vesicles. Specific loss of CLA-1L results in synaptic vesicle clustering defects and increased synaptic depression, but not in reduced synapse number or mini frequency. Together our data indicate that specific isoforms of clarinet serve distinct functions, regulating synapse development, synaptic vesicle clustering and release.