Fig. 6. Cargo-dependent size distribution and mobility of ERES. (a) Distribution of normalized sizes of ERES, p(a), in untreated (blue) and CHX-treated (red) CHO cells. The experimental data (histograms) are best described by a lognormal distribution (Eqn 3; colored dashed lines), indicating strong deviations of the individual ERES size from the mean <a>=1. Treatment with CHX increased the fraction of small ERES, meaning that the typical size (indicated by the peak of the distribution) shifted to smaller sizes. (b) The average diffusion coefficient D() of the ERES population, as determined by single-particle tracking, shows initially subdiffusion and converges towards an asymptotic value D₀=const. (unbroken and dashed lines) that depends on the treatment. In general, addition of CHX resulted in a twofold enhancement of diffusion with and without treatment with NOC, in agreement with the observed larger portion of small-sized ERES.