Fig. 1

Modeling the Golgi ribbon as a linear array of mini-stacks. A Schematic representation of WPB biogenesis at the Golgi. In the context of the Golgi ribbon, the size of mini-stacks (highlighted in the green box) delimits that of transiting VWF quanta (red); at the Golgi exit site, the continuous lumen of the TGN allows co-packaging of adjacent quanta into nascent WPBs (orange). B On the left, a micrograph showing HUVECs immuno-stained for the plasma membrane (PM, with an anti-VE-cadherin antibody) and WPBs (with antibody which visualizes processed VWF at the Golgi and in WPBs) and counterstained for DNA (Nuclei) with Hoechst. On the right, WPBs have been segmented for quantification. Scale bar: 20 μm. C Measured WPB sizes (Additional file 1, Fig. S1A) were quantized by dividing the length of each organelle by the median quantum size (see text for details) and rounding to the nearest integer. D WPB size distributions as calculated from equation 1 at the indicated values of p, the probability of mini-stack occupancy by VWF quanta. E WPB size distribution calculated from Eq 1a, where p follows a probability distribution to account cell-to-cell variability in VWF expression