title: Geometry-Driven Polarity in Motile Amoeboid Cells.
abstract: Motile eukaryotic cells, such as leukocytes, cancer cells, and amoeba, typically move inside the narrow interstitial spacings of tissue or soil. While most of our knowledge of actin-driven eukaryotic motility was obtained from cells that move on planar open surfaces, recent work has demonstrated that confinement can lead to strongly altered motile behavior. Here, we report experimental evidence that motile amoeboid cells undergo a spontaneous symmetry breaking in confined interstitial spaces. Inside narrow channels, the cells switch to a highly persistent, unidirectional mode of motion, moving at a constant speed along the channel. They remain in contact with the two opposing channel side walls and alternate protrusions of their leading edge near each wall. Their actin cytoskeleton exhibits a characteristic arrangement that is dominated by dense, stationary actin foci at the side walls, in conjunction with less dense dynamic regions at the leading edge. Our experimental findings can be explained based on an excitable network model that accounts for the confinement-induced symmetry breaking and correctly recovers the spatio-temporal pattern of protrusions at the leading edge. Since motile cells typically live in the narrow interstitial spacings of tissue or soil, we expect that the geometry-driven polarity we report here plays an important role for movement of cells in their natural environment.
authors.affiliation: Institute of Physics und Astronomy, University of Potsdam, Potsdam, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Nagel
authors.affiliation: Department of Physics, University of Maryland, College Park, Maryland, United States of America.
authors.forename: Can
authors.initials: C
authors.lastname: Guven
authors.affiliation: Institute of Physics und Astronomy, University of Potsdam, Potsdam, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Theves
authors.affiliation: Department of Physics, University of Maryland, College Park, Maryland, United States of America.
authors.forename: Meghan
authors.initials: M
authors.lastname: Driscoll
authors.affiliation: Department of Physics, University of Maryland, College Park, Maryland, United States of America.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Losert
authors.affiliation: Institute of Physics und Astronomy, University of Potsdam, Potsdam, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Beta
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D016764:Cell Polarity / Q000502:physiology*; D002473:Cell Wall / Q000502:physiology; D003198:Computer Simulation; D004023:Dictyostelium / Q000166:cytology* / Q000502:physiology*; D056656:Lab-On-A-Chip Devices; D008954:Models, Biological; D009068:Movement / Q000502:physiology*