Table 2.

Simulated intra-Golgi transport of albumin mediated by vesicles, predicts extremely fast turnover of cisternal rims

DOI: http://dx.doi.org/10.7554/eLife.02009.020

Vesicle diameter (nm)	50		60		70
Number of cisternae	4	6	4	6	4	6
Steps for 90% equilibration	19,617	44,230	11,352	25,595	7149	16,120
Rim turnover time (s)	0.576	0.255	0.829	0.368	1.129	0.500

The size and geometry of the Golgi stack and vesicles used for the simulations are defined in the legend to Figure 6—figure supplement 1. The variable parameters used for the simulation are: diameter of vesicles (from 50 to 70 nm) and number of cisternae (between 4 and 6). Albumin transport is considered to proceed stepwise, where each step is defined as one vesicle detaching from each cisterna and fusing with an adjacent one. For the calculations presented here, the albumin concentration in the vesicles is considered to be 20% of that present in the cisterna (see Figure 5 and also legend to Figure 6—figure supplement 1). The number of steps required to achieve 90% equilibration of albumin across the stack was computed and the time required for a single turnover event of the cisternal rim (rim turnover time) was calculated as described in the legend to Figure 6—figure supplement 1. The rim turnover time varied from 0.25 to 1.12 s or in other words, the rim turns over from 4 to 1 times per second, depending on the condition used for the simulation. The results presented here are for the scenario 'a' (discussed in Figure 6—figure supplement 1) and the results are very similar even in the case of scenario 'b'.