title: Properties of intermediate filament networks assembled from keratin 8 and 18 in the presence of Mg²+.
abstract: The mechanical properties of epithelial cells are modulated by structural changes in keratin intermediate filament networks. To investigate the relationship between network architecture and viscoelasticity, we assembled keratin filaments from recombinant keratin proteins 8 (K8) and 18 (K18) in the presence of divalent ions (Mg(2+)). We probed the viscoelastic modulus of the network by tracking the movement of microspheres embedded in the network during assembly, and studied the network architecture using scanning electron microscopy. Addition of Mg(2+) at physiological concentrations (<1 mM) resulted in networks whose structure was similar to that of keratin networks in epithelial cells. Moreover, the elastic moduli of networks assembled in vitro were found to be within the same magnitude as those measured in keratin networks of detergent-extracted epithelial cells. These findings suggest that Mg(2+)-induced filament cross-linking represents a valid model for studying the cytoskeletal mechanics of keratin networks.
authors.affiliation: Institut für Experimentelle Physik, University of Ulm, Ulm, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Leitner
authors.forename: Tobias
authors.initials: T
authors.lastname: Paust
authors.forename: Othmar
authors.initials: O
authors.lastname: Marti
authors.forename: Paul
authors.initials: P
authors.lastname: Walther
authors.forename: Harald
authors.initials: H
authors.lastname: Herrmann
authors.forename: Michael
authors.initials: M
authors.lastname: Beil
mesh_terms: D045744:Cell Line, Tumor; D055119:Elastic Modulus / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects / Q000648:ultrastructure; D006801:Humans; D007382:Intermediate Filaments / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure; D053538:Keratin-18 / Q000378:metabolism*; D053533:Keratin-8 / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology*; D008863:Microspheres
chemical_list: D053538:Keratin-18; D053533:Keratin-8; D008274:Magnesium