Fig. 5

Mini-stacks organized into a “breathing” ribbon. A Modeling interactions among mini-stacks; binding and unbinding rates (reaction scheme in Additional file 6, A) were calculated by solving a system of differential equations (Additional file 6, B). Two examples of fitted frequencies of Golgi of size 1 - 5 l (i.e., 1 - 5 mini-stacks) obtained by posing r = 0.001, d₁ = 100, total number of mini-stacks = 100000 and d₂ at the indicated values. B Relative frequencies of Golgi pieces of different lengths (in mini-stacks) from two experiments with nocodazole-treated cells, together with the predictions from the model with the best fit values of d₁ and d₂ (each fitted to the nearest whole number). C A “breathing” Golgi ribbon model is schematized. Occurrence of weak bonds between monomers and stable dimers predicts their dynamic linking/unlinking and possible rearrangement within the ribbon. The model shows that the number of stable mini-stack dimers is the same as that of monomers as measured in our experiments (Fig. 4A)