Role of Active Trafficking Dynamics on the Shape and Morphogenesis of Subcellular Compartments*

We study the role of membrane trafficking on the morphology of subcellular comparments, such as those encountered within the eukaryotic cell. These continuously interchange material amongst themselves via small transport vesicles, along closely regulated trafficking pathways. The processes of fission and fusion are orchestrated by a highly complex biochemical network of proteins. We develop a general theory which allows us to study the dynamical interplay of such active processes of fusion and fission with the membrane morphology as well as the hydrodynamics of the ambient fluid. This is facilitated by an appropriate coarse-graining over the microscopic biochemical reactions, which provides us with the large-scale properties of such active membranes. Here, the activity leads to a dynamical renormalization of the membrane parameters, which in turn drives the membrane to nonequilibrium steady-states with distinct morphologies that have no analogue in equilibrium physics. For instance, even under conditions of spatially isotropic activity, the membrane may spontaneously acquire a drift. We believe that these biophysical processes could play an important role to organelles such as golgi and endosomes.