Subdiffusion Arising from Intracellular Phase Separation

The intracellular environment of the cell, or cytoplasm, is a multicomponent mixture that is home to many active biological processes. It has been experimentally shown for a range of systems and contexts, including Saccharomyces cerevisiae, Escherichia coli, and mammalian cell lines, that proteins and nucleic acids in the cytoplasm undergo non-Gaussian anomalous diffusion even in the absence of evident viscoelastic cytoskeletal networks. One potential mechanism that could lead to these dynamics is liquid-liquid phase separation. Here, we report the properties of a system in and near the regime of phase separation, using molecular dynamics and Monte Carlo lattice simulations. We recover subdiffusion with exponentially decaying step-size distributions as have been observed in experiment and describe slowing in the vicinity of a critical point. Finally, we propose that phase separation allows the cell to actively tune and organize its interior.