Dynamic mapping of individual molecules and their compartments by high-density single particle tracking.

Abstract

Organization by compartmentalization is a general property of natural systems that efficiently facilitates and orchestrates biological events in space and time. In the last two decades, compartmentalization of the plasma membrane of living cells has emerged as a dominant feature present at different spatiotemporal scales and regulating key cell functions. The advent of super-resolution microscopy and single molecule dynamic approaches has allowed the study of the cell membrane with unprecedented levels of details. While super-resolution microscopy provides nanometer-scale snapshots of membrane organization, its poor temporal resolution precludes dynamic studies at the relevant temporal scales. On the other hand, single particle tracking (SPT) approaches are superior in terms of temporal resolution, but they are limited to a sub-set of labeled molecules, hindering detailed studies over the whole population of molecules. Here, I will discuss an approach based on high-density, multicolor SPT to map how individual molecules explore their nano- and meso-scale environment, and importantly, to reveal dynamic interactions with different components of the cell membrane. We find that both molecular diffusion and dynamic re-modelling of the environment play key roles regulating biological function.