Image-based model of diffusion on the endoplasmic reticulum

We use a coarse-grained model of random walks on networks to efficiently simulate the diffusion of biomolecules along the endoplasmic reticulum (ER). Along each ER tubule, the diffusion process may be conceptualized as a one-dimensional gambler’s ruin problem. By computing the mean first passage times (MFPT) to diffuse across the ER network, we connect network structure to the typical time required for synthesized proteins and other biomolecules to traverse the ER. We explore how network dynamics affect the MFPT and apply the model to data from Drosophila melanogaster neuromuscular junctions.