Synaptotagmin oligomers are necessary and can be sufficient to form a Ca2+‐sensitive fusion clamp. Issue 2 (18th January 2019)

• Record Type: Journal Article
• Authors: Ramakrishnan, Sathish; Bera, Manindra; Coleman, Jeff; Krishnakumar, Shyam S.; Pincet, Frederic; Rothman, James E.
• Is Part Of: FEBS letters. Volume 593:Issue 2(2019)
• Page Start: 154
• Page End: 162
• Publication Date: 2019-01-18
• Subjects: calcium -- fusion clamp -- single‐vesicle analysis -- SNARE proteins -- Synaptotagmin; Biochemistry -- Periodicals; Biophysics -- Periodicals; Molecular biology -- Periodicals; Biochimie -- Périodiques; Biochemistry; Biophysics; Molecular biology; Periodicals; 572.05
• DOI: 10.1002/1873-3468.13317
• Languages: English
• ISSNs: 0014-5793

Abstract

Abstract : The buttressed‐ring hypothesis, supported by recent cryo‐electron tomography analysis of docked synaptic‐like vesicles in neuroendocrine cells, postulates that prefusion SNAREpins are stabilized and organized by Synaptotagmin (Syt) ring‐like oligomers. Here, we use a reconstituted single‐vesicle fusion analysis to test the prediction that destabilizing the Syt1 oligomers destabilizes the clamp and results in spontaneous fusion in the absence of Ca 2+ . Vesicles in which Syt oligomerization is compromised by a ring‐destabilizing mutation dock and diffuse freely on the bilayer until they fuse spontaneously, similar to vesicles containing only v‐SNAREs. In contrast, vesicles containing wild‐type Syt are immobile as soon as they attach to the bilayer and remain frozen in place, up to at least 1 h until fusion is triggered by Ca 2+ . Abstract :