FIGURE 3 

Rab5 membrane density increases towards the conversion event. (A) Time-course data of Rab5 density on 23 individual endosomes tracked in 3 independent experiments (each value per time point shown by a dot) and a representative time course (black) are shown as a function of time. The average over 23 data points at each time point is given by the green curve together with the 70% confidence interval in grey. For each tracked endosome, the time point of conversion was determined by visual inspection and the recorded time courses were shifted by the conversion time point such that all 23 conversion events were synchronized at the chosen time point 0. Rab5 density has been computed by dividing the integral fluorescence by twice the cross-sectional area (Rink et al, 2005). Red curves denote model simulations for model 1 (dashed) and model 2 (solid curve), which were rescaled with respect to Figure 4C and D by (t-825)/4 t, (R₅-0.18)13 000+10 000 R₅ for model 1 and (t-850)/4-t, (R₅-0.6)20 000+10 000 R₅ for model 2. (B) Analogously obtained and analysed data for Rab7 density on 15 converting endosomes from an independent experiment.