  The analysis of single particle trajectories plays an important role in
elucidating dynamics within complex environments such as those found in living
cells. However, the characterization of intracellular particle motion is often
confounded by confinement of the particles within non-trivial subcellular
geometries. Here, we focus specifically on the case of particles undergoing
Brownian motion within a tubular network, as found in some cellular organelles.
An unraveling algorithm is developed to uncouple particle motion from the
confining network structure, allowing for an accurate extraction of the
diffusion coefficient, as well as differentiating between Brownian and
fractional Brownian dynamics. We validate the algorithm with simulated
trajectories and then highlight its application to an example system: analyzing
the motion of membrane proteins confined in the tubules of the peripheral
endoplasmic reticulum in mammalian cells. We show that these proteins undergo
diffusive motion with a well-characterized diffusivity. Our algorithm provides
a generally applicable approach for disentangling geometric morphology and
particle dynamics in networked architectures.
