Adhesion by Duf (red) triggers the translocation of vesicles with Rols7 (green) and more Duf to the adhesion site.
Translocation was initiated by adhesion of Duf's extracellular domain to an fcm ligand. The intracellular domain of the adhered Duf then transmitted an unknown signal that recruited puncta (probably endosomes) containing more Duf to the adhesion site. This Duf was then inserted into the membrane to attract a new fcm to the same spot where the previous fcm fused.
Duf translocation requires another puncta-localized protein called Rols7. In the absence of Rols7, only one round of fusion was possible, as Duf was not replenished. Rols7 must have an additional function during fusion, since a mutant that was missing multiple domains translocated effectively but did not support multiple rounds of fusion.