The kinetic evidence, which consists of the observation that albumin traverses the stack in less than 2 min, at least fivefold to sixfold faster than PC, is consistent with diffusional transport, a fast process over short distances.
Large soluble aggregates, which traverse the stack, do not transfer between Golgi, implying that small cargo (which can fit in a typical transport vesicle) are transported by a different mechanism.
The question how, and even whether, newly synthesized membrane and cargo proteins traverse the stacked Golgi cisternae, is a major point of debate.
But how do the proteins traverse the Golgi stack?
We think that such an overlap is fairly compelling evidence that the albumin traverses the Golgi stack faster than PC even under steady state conditions.
DOI: http://dx.doi.org/10.7554/eLife.01296.004 Most proteins require about 10 20 min to fully traverse the Golgi stack at 37°C, and this process is expected to be several fold slower at 20°C.
Moreover the use of Golgi ministacks where the separation between the cis and trans Golgi is always clearer than that seen with the intact Golgi ribbon provides a further convincing argument that even under steady state conditions the albumin traverses the Golgi stack faster than VSVG or PC.
At the same time, non-diffusible cargoes that cannot enter intercisternal tubules (such as PC-I) traverse the stack slowly, by progression maturation (Mironov et al., 2001).
A person could make it more than a fourth of the way to the moon traversing the tower of cash that would arise if all those loan dollars were stacked up one on top of the other – all $1,181,622,000,000-plus 1,181,622,000,000-plus of
Voices traverse the space.
