Table S1.

Data summary table for the number of analyzed subtomograms in Figs. 2–4

Vesicles	No. of loose point contacts (with no C1C2BMUN at or near site)	No. of tight point contacts (with no C1C2BMUN at or near site)	No. of long contacts	No. of cases with C1C2BMUN near contact site	No. of cases with C1C2BMUN at contact site	No. of hemifusion diaphragms	Total no. of analyzed contact sites	Total no. of vesicles without contacts
SV + PM	59	84	32	N/A	N/A	0	175	183
SVCpx + PM	74	218	37	N/A	N/A	0	329	287
SVCpx + PMC1C2BMUN	50	94	0	179	113	0	436	338
SVCpx + PM + Ca2+	18	35	83	N/A	N/A	66	202	136
SVCpx + PMC1C2BMUN + Ca2+	0	0	25	0	0	21	46	237

N/A, not applicable.