Membrane bridging by Munc13-1 is crucial for neurotransmitter release.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30816091.
- Also identified by DOI 10.7554/eLife.42806 and PMC identifier 6407922.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Munc13-1 plays a crucial role in neurotransmitter release. We recently proposed that the C-terminal region encompassing the C<sub>1</sub>, C<sub>2</sub>B, MUN and C<sub>2</sub>C domains of Munc13-1 (C<sub>1</sub>C<sub>2</sub>BMUNC<sub>2</sub>C) bridges the synaptic vesicle and plasma membranes through interactions involving the C<sub>2</sub>C domain and the C<sub>1</sub>-C<sub>2</sub>B region. However, the physiological relevance of this model has not been demonstrated. Here we show that C<sub>1</sub>C<sub>2</sub>BMUNC<sub>2</sub>C bridges membranes through opposite ends of its elongated structure. Mutations in putative membrane-binding sites of the C<sub>2</sub>C domain disrupt the ability of C<sub>1</sub>C<sub>2</sub>BMUNC<sub>2</sub>C to bridge liposomes and to mediate liposome fusion in vitro. These mutations lead to corresponding disruptive effects on synaptic vesicle docking, priming, and Ca<sup>2+</sup>-triggered neurotransmitter release in mouse neurons. Remarkably, these effects include an almost complete abrogation of release by a single residue substitution in this 200 kDa protein. These results show that bridging the synaptic vesicle and plasma membranes is a central function of Munc13-1.
Medical subject headings
- Nerve Tissue Proteins
- Neurons
- Neurotransmitter Agents