Fig.

6. Endosome maturation to endosome formation model. The model describes the stepwise maturation pattern that gives rise to new Rab5-positive vesicles. A newly internalized Rab5-positive endosome can fuse with itself and pre-existing Rab5-positive endosomes. Maturation from Rab5- to Rab7a-positive endosomes takes place in two phases. (1) Rab7a-independent initial diffusion-like Rab5 detachment. (2) Convergence phase, during which Rab5-positive domains are formed and converge towards one main domain. This phase is dependent on Rab7a-positive endosome interaction to provide and/or supply Rab7a to the maturing endosome. Finally, the converged domains leave the matured endosome to generate new and fully functional Rab5-positive endosomes that will be primed for the next round of endosomal sorting through maturation (see main article for detailed description).