| Autor: |
Li F; Department of Cell Biology, School of Medicine, Yale University, New Haven, CT 06520.; Nanobiology Institute, School of Medicine, Yale University, West Haven, CT 06516., Grushin K; Department of Cell Biology, School of Medicine, Yale University, New Haven, CT 06520.; Nanobiology Institute, School of Medicine, Yale University, West Haven, CT 06516., Coleman J; Department of Cell Biology, School of Medicine, Yale University, New Haven, CT 06520.; Nanobiology Institute, School of Medicine, Yale University, West Haven, CT 06516., Pincet F; Department of Cell Biology, School of Medicine, Yale University, New Haven, CT 06520.; Nanobiology Institute, School of Medicine, Yale University, West Haven, CT 06516.; Laboratoire de Physique de l'Ecole normale supérieure, Département de Physique, Ecole Normale Supérieure, Université Paris Sciences & Lettres CNRS, Sorbonne Université, Université de Paris, Paris F-75005, France., Rothman JE; Department of Cell Biology, School of Medicine, Yale University, New Haven, CT 06520.; Nanobiology Institute, School of Medicine, Yale University, West Haven, CT 06516. |
| Abstrakt: |
Munc13-1 is essential for vesicle docking and fusion at the active zone of synapses. Here, we report that Munc13-1 self-assembles into molecular clusters within diacylglycerol-rich microdomains present in phospholipid bilayers. Although the copy number of Munc13-1 molecules in these clusters has a broad distribution, a systematic Poisson analysis shows that this is most likely the result of two molecular species: monomers and mainly hexameric oligomers. Each oligomer is able to capture one vesicle independently. Hexamers have also been observed in crystals of Munc13-1 that form between opposed phospholipid bilayers [K. Grushin, R. V. Kalyana Sundaram, C. V. Sindelar, J. E. Rothman, Proc. Natl. Acad. Sci. U.S.A. 119 , e2121259119 (2022)]. Mutations targeting the contacts stabilizing the crystallographic hexagons also disrupt the isolated hexamers, suggesting they are identical. Additionally, these mutations also convert vesicle binding from a cooperative to progressive mode. Our study provides an independent approach showing that Munc13-1 can form mainly hexamers on lipid bilayers each capable of vesicle capture. |
