Figure 7. Numerical simulations show protein aggregation induced by impairment of trafficking.

(a) The main figure shows the average number of aggregates observed at a fixed time as a function of k_out/k_in, the ratio between rate of exit from the ER by means of vesicular transport and the rate of protein production. A reduced value of k_out leads to the formation of aggregates. The inset shows the time dependence of the average number of aggregates for different values of k_out. (b) The phase diagram of the vesicle formation model. The stiffness ratio between the membrane and the external scaffold K_m/K_s as a function of the intensity of the mutual interaction with respect to the scaffold rigidity ε_LJ/K_s. For soft membranes there is almost always vesicle formation (yellow zone) or the breaking of the coat-membrane interface, if binding is not strong enough (white zone). Increasing the membrane stiffness leads to a new phase appears where the coat-membrane interface is stable but vesicle can not form (grey zone). Typical configurations in the different phases are reported on the right-hand side of the panel.