--------------------
- Vesicle capture by membrane-bound Munc13-1 requires selfassembly into discrete clusters doi link

Auteur(s): Li Feng, Sundaram Venkat, Gatta Alberto, Coleman Jeff, Ramakrishnan S., Krishnakumar Shyam, Pincet Frederic, Rothman James

(Article) Publié: Febs Letters, vol. 595 p.2185-2196 (2021)
Texte intégral en Openaccess : fichier pdf


Ref HAL: hal-03297036_v1
DOI: 10.1002/1873-3468.14157
Exporter : BibTex | endNote
Résumé:

Munc13-1 is a large banana-shaped soluble protein that is involved in the regulation of synaptic vesicle docking and fusion. Recent studies suggest that multiple copies of Munc13-1 form nanoassemblies in active zones of neurons. However, it is not known if such clustering of Munc13-1 is correlated with multivalent binding to synaptic vesicles or specific plasma membrane domains at docking sites in the active zone. The functional significance of putative Munc13-1 clustering is also unknown. Here we report that nano-clustering is an inherent property of Munc13-1, and is indeed required for vesicle binding to bilayers containing Munc13-1. Purified Munc13-1 protein reconstituted onto supported lipid bilayers assembled into clusters containing from 2 to ~20 copies as revealed by a combination of quantitative TIRF microscopy and step-wise photobleaching. Surprisingly, only clusters containing a minimum of 6 copies of Munc13-1 were capable of efficiently capturing and retaining small unilamellar vesicles. The C-terminal C 2 C domain of Munc13-1 is not required for Munc13-1 clustering, but is required for efficient vesicle capture. This capture is largely due to a combination of electrostatic and hydrophobic interactions between the C 2 C domain and the vesicle membrane.