Distribution of SNARE for large number of cisternae.

<p>The steady state gradient has the exponentially decaying form, where depends on two dimensionless groups of parameters, which caracterizes the decay of the SNARE and which characterizes the vesicular transport of SNARE: and (solid line) with the best fit given by , and (dashed line) with the best fit given by . Theoretical values of determined from (11) are indistinguishable from the values obtained as the best fit for the simulations. The dotted line corresponds to the case of zero loss, and , and illustrates the absence of a concentration gradient. To reveal the exponential decay of the SNARE concentration, we purposefully consider a non-biologically high number of compartments and analyze the SNARE concentration away from both the <i>cis</i> and <i>trans</i> ends of the stack, where the boundary effects can play a role.