Anomalous diffusion and compartmentalization on the surface of mammalian cells

by Diego Krapf (Colorado State University, CO, USA)

Wednesday 22 Jun 2016, 12:00 → 13:00 Europe/Rome

Aula 2 (Dip. di Fisica - Edificio E. Fermi)

Tracking individual proteins on the surface of live mammalian cells
reveals complex dynamics involving anomalous diffusion. Theoretical models show that anomalous subdiffusion can be caused by different processes. By performing time series and ensemble analysis of extensive single-molecule tracking we show that two anomalous subdiffusion processes simultaneously coexist and only one of them is ergodic. Weak ergodicity breaking is found to be maintained by immobilization events that take place when the proteins are captured within endocytic pits. Furthermore, using a combination of dynamic super-resolution imaging and single-particle tracking, we observe that the actin cytoskeleton introduces barriers leading to the compartmentalization of the plasma membrane and that proteins are transiently confined within actin domains. Our results show that the actin-induced compartments are scale free and that the actin cortex forms a self-similar fractal structure.