title: Superdiffusion dominates intracellular particle motion in the supercrowded cytoplasm of pathogenic Acanthamoeba castellanii.
abstract: Acanthamoebae are free-living protists and human pathogens, whose cellular functions and pathogenicity strongly depend on the transport of intracellular vesicles and granules through the cytosol. Using high-speed live cell imaging in combination with single-particle tracking analysis, we show here that the motion of endogenous intracellular particles in the size range from a few hundred nanometers to several micrometers in Acanthamoeba castellanii is strongly superdiffusive and influenced by cell locomotion, cytoskeletal elements, and myosin II. We demonstrate that cell locomotion significantly contributes to intracellular particle motion, but is clearly not the only origin of superdiffusivity. By analyzing the contribution of microtubules, actin, and myosin II motors we show that myosin II is a major driving force of intracellular motion in A. castellanii. The cytoplasm of A. castellanii is supercrowded with intracellular vesicles and granules, such that significant intracellular motion can only be achieved by actively driven motion, while purely thermally driven diffusion is negligible.
authors.affiliation: Institute for Materials Science, Biocompatible Nanomaterials, Christian-Albrechts-Universität zu Kiel, Kaiserstr. 2, D-24143 Kiel, Germany.
authors.forename: Julia F
authors.initials: JF
authors.lastname: Reverey
authors.affiliation: School of Physics, Korea Institute for Advanced Study, Seoul 130-722, Republic of Korea.
authors.forename: Jae-Hyung
authors.initials: JH
authors.lastname: Jeon
authors.affiliation: Institute for Materials Science, Biocompatible Nanomaterials, Christian-Albrechts-Universität zu Kiel, Kaiserstr. 2, D-24143 Kiel, Germany.
authors.forename: Han
authors.initials: H
authors.lastname: Bao
authors.affiliation: Zoological Institute, Comparative Immunobiology, Christian-Albrechts-Universität zu Kiel, Olshausenstr.40, D-24098 Kiel, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Leippe
authors.affiliation: 1] Institute of Physics &Astronomy, University of Potsdam, D-14776 Potsdam-Golm, Germany [2] Department of Physics, Tampere University of Technology, FI-30101 Tampere, Finland.
authors.forename: Ralf
authors.initials: R
authors.lastname: Metzler
authors.affiliation: Institute for Materials Science, Biocompatible Nanomaterials, Christian-Albrechts-Universität zu Kiel, Kaiserstr. 2, D-24143 Kiel, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Selhuber-Unkel
mesh_terms: D048248:Acanthamoeba castellanii / Q000502:physiology*; D008841:Actin Cytoskeleton; D000199:Actins / Q000378:metabolism; D002465:Cell Movement; D003593:Cytoplasm / Q000378:metabolism*; D004058:Diffusion; D008870:Microtubules / Q000378:metabolism; D024462:Myosin Type II / Q000378:metabolism; D059008:Time-Lapse Imaging
chemical_list: D000199:Actins; D024462:Myosin Type II