Figure 3.

The C2C and C2D domains are indispensable for Ca²⁺-stimulated lipid transfer mediated by Tcb3.A, schematic diagrams of WTˆ and mutant Tcb3 proteins. B, lipid transfer of the protein-free liposomes in the absence or presence of 1 μM Tcb3 (WTˆ or mutants). The lipid transfer reactions included 0.1 mM EGTA or CaCl₂. C, initial lipid transfer rates of NBD-labeled phosphatidylethanolamine in the reactions shown in B. The dashed line indicates the level of Ca²⁺-independent lipid transfer. Error bars indicate standard deviation. Data are presented as mean ± SD (n = 3 independent replicates). p Values were calculated using two-way ANOVA with Tukey’s multiple comparisons test. n.s., p > 0.05. ∗∗∗∗p < 0.0001. F (7, 32) = 48.02, p < 0.0001 for protein factor and F (1, 32) = 238.8, p < 0.0001 for Ca²⁺ factor. A significant interaction between the two factors is F (7, 32) = 34.34, p < 0.0001.