Figure 4. Annexin A2 is required for homotypic Atg16L⁺ vesicle fusion.

(a–d) Analysis of Atg16L⁺/annexin A2⁺ vesicles fusion events at different Ca²⁺ concentrations; Atg16L⁺/annexin A2⁺ vesicles were sorted with Alexa-488 or Texas-Red-conjugated antibody to obtain mixed colour-positive vesicles. In vitro fusion was analysed at different Ca²⁺ concentrations. Single vesicles refer to structures as depicted in b; double vesicles refer to structures as depicted in c and multiple fusion refers to structures as depicted in d; the mean and s.e. were calculated from n>300 events. *P<0.05; **P<0.01; ****P<0.0001. (e) Ultrastructural analysis of phagophore-like structures derived from the in vitro fusion of Atg16L⁺/annexin A2⁺ vesicles. (f) Quantification of fusion events among Atg16L⁺ vesicles sorted from Anxa2^+/+ and Anxa2^−/− DCs; the mean and s.e. were calculated from n>300 events. **P<0.01; ***P<0.001. (g,h) Quantification of fusion events among Atg-16L vesicles sorted from Anxa2^+/+ and Anxa2^−/− DCs, plus or minus reconstitution with annexin A2; the mean and s.e. were calculated from n>300 events. *P<0.05; ****P<0.0001 (all unpaired two-tailed Student’s t-test).