Supplementary Figure 7: Correlation between membrane penetration activity and the ability of syt linker mutants to drive Ca2+-triggered lipid mixing in a reconstituted membrane fusion assay.
From: Linker mutations reveal the complexity of synaptotagmin 1 action during synaptic transmission
(a) A schematic diagram of the reconstituted fusion system; the donor (NBD) fluorescence increases, due to dequenching, upon fusion. (b, c) Representative traces of reconstituted membrane fusion reactions regulated by WT or linker mutant forms of syt; the arrow indicates the addition of Ca2+ (1 mM free). (d) Scatter plot of the extent of fusion 1 h after addition of Ca2+. For each condition, four independent experiments were carried out. (e, f) Positive correlation between membrane penetration of loop 3 in either C2A or C2B, taken from Fig. 4c,f, with the extent of fusion. Plotted values represent the mean ± SEM. Statistical significance was determined using a bootstrap approach. Asterisks indicate differences compared with WT; * p < 0.05, ** p < 0.01. Detailed statistical analysis, and equations and p-values for the linear regressions, are provided in Supplementary Table 1.
