Spatiotemporal fluctuations of protein folding in living cells

Protein folding landscapes and protein-protein interaction landscapes are subject to modulation by many factors inside living cells: crowding, electrostatics, hydrophobic interactions, and even hydrodynamic phenomena. The resulting spatiotemporal fluctuations in protein folding rates, protein stability, protein structure, protein function, and protein interactions are the subject of a recent generation of experiments, as well as in-cell modeling. We discuss some specific examples of how the cell modulates energy landscapes and leads to fluctuations that may, in some cases, simply be a consequence of statistical physics, but, in other cases, may be exploited by the cell to improve its fitness.