title: Ring-like oligomers of Synaptotagmins and related C2 domain proteins.
abstract: We recently reported that the C2AB portion of Synaptotagmin 1 (Syt1) could self-assemble into Ca(2+)-sensitive ring-like oligomers on membranes, which could potentially regulate neurotransmitter release. Here we report that analogous ring-like oligomers assemble from the C2AB domains of other Syt isoforms (Syt2, Syt7, Syt9) as well as related C2 domain containing protein, Doc2B and extended Synaptotagmins (E-Syts). Evidently, circular oligomerization is a general and conserved structural aspect of many C2 domain proteins, including Synaptotagmins. Further, using electron microscopy combined with targeted mutations, we show that under physiologically relevant conditions, both the Syt1 ring assembly and its rapid disruption by Ca(2+) involve the well-established functional surfaces on the C2B domain that are important for synaptic transmission. Our data suggests that ring formation may be triggered at an early step in synaptic vesicle docking and positions Syt1 to synchronize neurotransmitter release to Ca(2+) influx.
authors.affiliation: Department of Cell Biology, Yale School of Medicine, New Haven, United States.
authors.forename: Maria N
authors.initials: MN
authors.lastname: Zanetti
authors.affiliation: Department of Cell Biology, Yale School of Medicine, New Haven, United States.
authors.forename: Oscar D
authors.initials: OD
authors.lastname: Bello
authors.affiliation: Department of Cell Biology, Yale School of Medicine, New Haven, United States.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Cell Biology, Yale School of Medicine, New Haven, United States.
authors.forename: Jeff
authors.initials: J
authors.lastname: Coleman
authors.affiliation: Department of Cell Biology, Yale School of Medicine, New Haven, United States.
authors.forename: Yiying
authors.initials: Y
authors.lastname: Cai
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, New Haven, United States.
authors.forename: Charles V
authors.initials: CV
authors.lastname: Sindelar
authors.affiliation: Department of Cell Biology, Yale School of Medicine, New Haven, United States.
authors.forename: James E
authors.identifier: 0000-0001-8653-8650
authors.initials: JE
authors.lastname: Rothman
authors.affiliation: Department of Cell Biology, Yale School of Medicine, New Haven, United States.
authors.forename: Shyam S
authors.identifier: 0000-0001-6148-3251
authors.initials: SS
authors.lastname: Krishnakumar
mesh_terms: D000070538:C2 Domains; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization; D050857:Synaptotagmins / Q000378:metabolism*; D053835:Unilamellar Liposomes
chemical_list: D002135:Calcium-Binding Proteins; C490420:DOC2B protein, human; D009419:Nerve Tissue Proteins; D053835:Unilamellar Liposomes; D050857:Synaptotagmins; D002118:Calcium
keywords: biophysics; electron microscopy; membrane fusion; neuroscience; neurotransmitters; none; structural biology