The principal constituent of the living cell is water. The role of the hydration shell and bulk ${\mathrm{H}}_2$O solvent is well recognized in the dynamics of isolated proteins, but the role of water in the dynamics of the integrated living cytoskeleton (CSK) remains obscure. Here we report a direct connection of dynamics of water to dynamics of the integrated CSK. The latter are known to be scale-free and to hinge upon a frequency $f_0$ that is roughly invariant across cell types. Although $f_0$ is comparable in magnitude to the rotational relaxation frequency of water (gigahertz range), the physical basis of $f_0$ remains unknown. Using the human airway smooth muscle cell as a model system, we show here that replacing water acutely with deuterium oxide impacts CSK dynamics in major ways, slowing CSK remodeling dynamics appreciably, and lowering $f_0$ by up to four orders of magnitude. Although these observations do not distinguish contributions of bulk solvent versus hydration shell, they suggest a unifying hypothesis, namely, that dynamics of integrated CSK networks are slaved in a direct fashion to fluctuations arising in intracellular water.

• Received 28 January 2011

DOI:https://doi.org/10.1103/PhysRevE.83.061918