title: Bacterial twitching motility is coordinated by a two-dimensional tug-of-war with directional memory.
abstract: Type IV pili are ubiquitous bacterial motors that power surface motility. In peritrichously piliated species, it is unclear how multiple pili are coordinated to generate movement with directional persistence. Here we use a combined theoretical and experimental approach to test the hypothesis that multiple pili of Neisseria gonorrhoeae are coordinated through a tug-of-war. Based on force-dependent unbinding rates and pilus retraction speeds measured at the level of single pili, we build a tug-of-war model. Whereas the one-dimensional model robustly predicts persistent movement, the two-dimensional model requires a mechanism of directional memory provided by re-elongation of fully retracted pili and pilus bundling. Experimentally, we confirm memory in the form of bursts of pilus retractions. Bursts are seen even with bundling suppressed, indicating re-elongation from stable core complexes as the key mechanism of directional memory. Directional memory increases the surface range explored by motile bacteria and likely facilitates surface colonization.
authors.affiliation: 1] Max Planck Institute of Colloids and Interfaces, Science Park Golm, Potsdam 14424, Germany [2] [3].
authors.forename: Rahul
authors.initials: R
authors.lastname: Marathe
authors.affiliation: 1] Department of Physics and Biocenter, University of Cologne, Zülpicher Strasse 77, Cologne 50937, Germany [2].
authors.forename: Claudia
authors.initials: C
authors.lastname: Meel
authors.affiliation: Department of Physics and Biocenter, University of Cologne, Zülpicher Strasse 77, Cologne 50937, Germany.
authors.forename: Nora C
authors.initials: NC
authors.lastname: Schmidt
authors.affiliation: Department of Physics and Biocenter, University of Cologne, Zülpicher Strasse 77, Cologne 50937, Germany.
authors.forename: Lena
authors.initials: L
authors.lastname: Dewenter
authors.affiliation: Department of Physics and Biocenter, University of Cologne, Zülpicher Strasse 77, Cologne 50937, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Kurre
authors.affiliation: Institute of Infectiology, Center for Molecular Biology of Inflammation, University of Münster, Von-Esmarch-Strasse 56, Münster 48149, Germany.
authors.forename: Lilo
authors.initials: L
authors.lastname: Greune
authors.affiliation: Institute of Infectiology, Center for Molecular Biology of Inflammation, University of Münster, Von-Esmarch-Strasse 56, Münster 48149, Germany.
authors.forename: M Alexander
authors.initials: MA
authors.lastname: Schmidt
authors.affiliation: FAS Center for Systems Biology, Harvard University, 52 Oxford Street, Cambridge, Massachusetts 02138, USA.
authors.forename: Melanie J I
authors.initials: MJ
authors.lastname: Müller
authors.affiliation: Max Planck Institute of Colloids and Interfaces, Science Park Golm, Potsdam 14424, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Lipowsky
authors.affiliation: Department of Physics and Biocenter, University of Cologne, Zülpicher Strasse 77, Cologne 50937, Germany.
authors.forename: Berenike
authors.initials: B
authors.lastname: Maier
authors.affiliation: Max Planck Institute of Colloids and Interfaces, Science Park Golm, Potsdam 14424, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Klumpp
mesh_terms: D036781:Fimbriae Proteins / Q000378:metabolism*; D010861:Fimbriae, Bacterial / Q000378:metabolism*; D008962:Models, Theoretical; D009068:Movement / Q000502:physiology*; D009344:Neisseria gonorrhoeae / Q000378:metabolism*; D013314:Stress, Mechanical
chemical_list: D036781:Fimbriae Proteins