title: Motor-driven intracellular transport powers bacterial gliding motility.
abstract: Protein-directed intracellular transport has not been observed in bacteria despite the existence of dynamic protein localization and a complex cytoskeleton. However, protein trafficking has clear potential uses for important cellular processes such as growth, development, chromosome segregation, and motility. Conflicting models have been proposed to explain Myxococcus xanthus motility on solid surfaces, some favoring secretion engines at the rear of cells and others evoking an unknown class of molecular motors distributed along the cell body. Through a combination of fluorescence imaging, force microscopy, and genetic manipulation, we show that membrane-bound cytoplasmic complexes consisting of motor and regulatory proteins are directionally transported down the axis of a cell at constant velocity. This intracellular motion is transmitted to the exterior of the cell and converted to traction forces on the substrate. Thus, this study demonstrates the existence of a conserved class of processive intracellular motors in bacteria and shows how these motors have been adapted to produce cell motility.
authors.affiliation: Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA.
authors.forename: Mingzhai
authors.initials: M
authors.lastname: Sun
authors.forename: Morgane
authors.initials: M
authors.lastname: Wartel
authors.forename: Eric
authors.initials: E
authors.lastname: Cascales
authors.forename: Joshua W
authors.initials: JW
authors.lastname: Shaevitz
authors.forename: Tâm
authors.initials: T
authors.lastname: Mignot
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D015153:Blotting, Western; D018274:Electroporation; D005452:Fluoresceins; D005453:Fluorescence; D022001:Focal Adhesions / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D047468:Immunoprecipitation; D007734:Kymography; D008124:Locomotion / Q000502:physiology*; D008863:Microspheres; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000378:metabolism*; D016941:Myxococcus xanthus / Q000502:physiology*; D010957:Plasmids / Q000235:genetics; D021381:Protein Transport / Q000502:physiology
chemical_list: D005452:Fluoresceins; D020409:Molecular Motor Proteins; C057433:2',7'-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl ester; D000255:Adenosine Triphosphate