title: Rapid microtubule self-assembly kinetics.
abstract: Microtubule assembly is vital for many fundamental cellular processes. Current models for microtubule assembly kinetics assume that the subunit dissociation rate from a microtubule tip is independent of free subunit concentration. Total-Internal-Reflection-Fluorescence (TIRF) microscopy experiments and data from a laser tweezers assay that measures in vitro microtubule assembly with nanometer resolution, provides evidence that the subunit dissociation rate from a microtubule tip increases as the free subunit concentration increases. These data are consistent with a two-dimensional model for microtubule assembly, and are explained by a shift in microtubule tip structure from a relatively blunt shape at low free concentrations to relatively tapered at high free concentrations. We find that because both the association and the dissociation rates increase at higher free subunit concentrations, the kinetics of microtubule assembly are an order-of-magnitude higher than currently estimated in the literature.
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Melissa K
authors.initials: MK
authors.lastname: Gardner
authors.forename: Blake D
authors.initials: BD
authors.lastname: Charlebois
authors.forename: Imre M
authors.initials: IM
authors.lastname: Jánosi
authors.forename: Jonathon
authors.initials: J
authors.lastname: Howard
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Hunt
authors.forename: David J
authors.initials: DJ
authors.lastname: Odde
mesh_terms: D000818:Animals; D002460:Cell Line; D007700:Kinetics; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D008954:Models, Biological; D013552:Swine; D014404:Tubulin / Q000378:metabolism
chemical_list: D008869:Microtubule-Associated Proteins; D014404:Tubulin