title: Actomyosin contractility and RhoGTPases affect cell-polarity and directional migration during haptotaxis.
abstract: Although much is known about chemotaxis- induced by gradients of soluble chemical cues - the molecular mechanisms involved in haptotaxis (migration induced by substrate-bound protein gradients) are largely unknown. We used micropatterning to produce discontinuous gradients consisting of μm-sized fibronectin-dots arranged at constant lateral but continuously decreasing axial spacing. Parameters like gradient slope, protein concentration and size or shape of the fibronectin dots were modified to determine optimal conditions for directional cell migration in gradient patterns. We demonstrate that fibroblasts predominantly migrate uphill towards a higher fibronectin density in gradients with a dot size of 2 × 2 μm, a 2% and 6% slope, and a low fibronectin concentration of 1 μg ml-1. Increasing dot size to 3.5 × 3.5 μm resulted in stationary cells, whereas rectangular dots (2 × 3 μm) orientated perpendicular to the gradient axis preferentially induce lateral migration. During haptotaxis, the Golgi apparatus reorients to a posterior position between the nucleus and the trailing edge. Using pharmacological inhibitors, we demonstrate that actomyosin contractility and microtubule dynamics are a prerequisite for gradient recognition indicating that asymmetric intracellular forces are necessary to read the axis of adhesive gradients. In the haptotaxis signalling cascade, RhoA and Cdc42, and the atypical protein kinase C zeta (aPKCζ), but not Rac, are located upstream of actomyosin contractility.
authors.affiliation: Zoological Institute, Department of Cell- and Neurobiology, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany. bastmeyer@kit.edu and DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1, 76131 Karlsruhe, Germany and Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Tatjana J
authors.initials: TJ
authors.lastname: Autenrieth
authors.affiliation: Zoological Institute, Department of Cell- and Neurobiology, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany. bastmeyer@kit.edu and Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Stephanie C
authors.initials: SC
authors.lastname: Frank
authors.affiliation: Zoological Institute, Department of Cell- and Neurobiology, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany. bastmeyer@kit.edu.
authors.forename: Alexandra M
authors.initials: AM
authors.lastname: Greiner
authors.affiliation: Zoological Institute, Department of Cell- and Neurobiology, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany. bastmeyer@kit.edu.
authors.forename: Dominik
authors.initials: D
authors.lastname: Klumpp
authors.affiliation: Zoological Institute, Department of Cell- and Neurobiology, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany. bastmeyer@kit.edu and Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1, 76131 Karlsruhe, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Richter
authors.affiliation: Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1, 76131 Karlsruhe, Germany.
authors.forename: Mario
authors.initials: M
authors.lastname: Hauser
authors.affiliation: Department of Neurobiology and Behavior, Stony Brook University, Stony Brook NY, USA.
authors.forename: Seong-Il
authors.initials: SI
authors.lastname: Lee
authors.affiliation: Department of Neurobiology and Behavior, Stony Brook University, Stony Brook NY, USA.
authors.forename: Joel
authors.initials: J
authors.lastname: Levine
authors.affiliation: Zoological Institute, Department of Cell- and Neurobiology, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany. bastmeyer@kit.edu and DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1, 76131 Karlsruhe, Germany and Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Bastmeyer
mesh_terms: D000205:Actomyosin / Q000502:physiology*; D000818:Animals; D016764:Cell Polarity; D002478:Cells, Cultured; D002633:Chemotaxis / Q000502:physiology*; D002642:Chick Embryo; D005109:Extracellular Matrix / Q000502:physiology; D016326:Extracellular Matrix Proteins / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology*; D005353:Fibronectins / Q000378:metabolism*; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D013314:Stress, Mechanical; D020741:rho GTP-Binding Proteins / Q000502:physiology*
chemical_list: D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D000205:Actomyosin; D020741:rho GTP-Binding Proteins