Synaptotagmin-1 C2B domain interacts simultaneously with SNAREs and membranes to promote membrane fusion.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 27083046.
- Also identified by DOI 10.7554/eLife.14211 and PMC identifier 4878868.
- 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
Synaptotagmin-1 (Syt1) acts as a Ca(2+) sensor for neurotransmitter release through its C2 domains. It has been proposed that Syt1 promotes SNARE-dependent fusion mainly through its C2B domain, but the underlying mechanism is poorly understood. In this study, we show that the C2B domain interacts simultaneously with acidic membranes and SNARE complexes via the top Ca(2+)-binding loops, the side polybasic patch, and the bottom face in response to Ca(2+). Disruption of the simultaneous interactions completely abrogates the triggering activity of the C2B domain in liposome fusion. We hypothesize that the simultaneous interactions endow the C2B domain with an ability to deform local membranes, and this membrane-deformation activity might underlie the functional significance of the Syt1 C2B domain in vivo.
Medical subject headings
- Calcium
- Membrane Fusion
- Membranes
- SNARE Proteins
- Synaptotagmin I