title: Dynamics of the cytoskeleton: how much does water matter?
abstract: The principal constituent of the living cell is water. The role of the hydration shell and bulk 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.
authors.affiliation: School of Public Health, Harvard University, Boston, Massachusetts 02115, USA. glenorma@hsph.harvard.edu
authors.forename: Guillaume
authors.initials: G
authors.lastname: Lenormand
authors.forename: Emil
authors.initials: E
authors.lastname: Millet
authors.forename: Chan Young
authors.initials: CY
authors.lastname: Park
authors.forename: C Corey
authors.initials: CC
authors.lastname: Hardin
authors.forename: James P
authors.initials: JP
authors.lastname: Butler
authors.forename: Nicanor I
authors.initials: NI
authors.lastname: Moldovan
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Fredberg
mesh_terms: D001696:Biomechanical Phenomena; D002470:Cell Survival / Q000187:drug effects; D003599:Cytoskeleton / Q000378:metabolism*; D017666:Deuterium Oxide / Q000494:pharmacology; D006801:Humans; D006860:Hydrogen Bonding / Q000187:drug effects; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects; D014867:Water / Q000378:metabolism*
chemical_list: D014867:Water; D017666:Deuterium Oxide