biostudies-literatureLi FNIDDK NIH HHSU.S. Department of Health & Human Services | NIH | National Institute of Diabetes and Digestive and Kidney Diseases (National Institute of Diabetes & Digestive & Kidney Diseases)1608https://www.ebi.ac.uk/biostudies/studies/S-EPMC11615320biostudies-literatureUnknown7(1)Synaptotagmin-1 (Syt-1) self-assembles into ring-like oligomers, and genetic and biochemical evidence suggest that oligomerization is needed to clamp synaptic vesicles and stabilize them for Ca²⁺-evoked release. However, oligomerization has not yet been demonstrated on lipid bilayers or studied in quantitative biophysical terms. Here we utilize single-molecule imaging methods to monitor the assembly and disassembly of oligomeric clusters of Syt-1 on lipid bilayers in real-time. Syt-1 assembled into two distinct classes of oligomers, small (5 ± 2 subunits) and large (15 ± 2 subunits). Each class assembled at a constant k_on that was always proportional to its ultimate size, but both classes disassembled at the same unit rate (k_off) independent of its size. BoCommunications biologyQuantitative single-molecule analysis of assembly and Ca<sup>2+</sup>-dependent disassembly of synaptotagmin oligomers on lipid bilayers.PMC11615320DK027044R01 DK027044R37 DK027044Redondo-Morata LLi FPincet FKalyana Sundaram RVStroeva EColeman JRothman JEfalseQuantitative single-molecule analysis of assembly and Ca<sup>2+</sup>-dependent disassembly of synaptotagmin oligomers on lipid bilayers.Synaptotagmin-1 (Syt-1) self-assembles into ring-like oligomers, and genetic and biochemical evidence suggest that oligomerization is needed to clamp synaptic vesicles and stabilize them for Ca²⁺-evoked release. However, oligomerization has not yet been demonstrated on lipid bilayers or studied in quantitative biophysical terms. Here we utilize single-molecule imaging methods to monitor the assembly and disassembly of oligomeric clusters of Syt-1 on lipid bilayers in real-time. Syt-1 assembled into two distinct classes of oligomers, small (5 ± 2 subunits) and large (15 ± 2 subunits). Each class assembled at a constant k_on that was always proportional to its ultimate size, but both classes disassembled at the same unit rate (k_off) independent of its size. Bo2024-01-01T00:00:00Z2024 Dec2025-04-04T01:05:08.535Z2025-04-04T01:05:08.535ZS-EPMC116153203962753910.1038/s42003-024-07317-9