title: Contact guidance requires spatial control of leading-edge protrusion.
abstract: In vivo, geometric cues from the extracellular matrix (ECM) are critical for the regulation of cell shape, adhesion, and migration. During contact guidance, the fibrillar architecture of the ECM promotes an elongated cell shape and migration along the fibrils. The subcellular mechanisms by which cells sense ECM geometry and translate it into changes in shape and migration direction are not understood. Here we pattern linear fibronectin features to mimic fibrillar ECM and elucidate the mechanisms of contact guidance. By systematically varying patterned line spacing, we show that a 2-μm spacing is sufficient to promote cell shape elongation and migration parallel to the ECM, or contact guidance. As line spacing is increased, contact guidance increases without affecting migration speed. To elucidate the subcellular mechanisms of contact guidance, we analyze quantitatively protrusion dynamics and find that the structured ECM orients cellular protrusions parallel to the ECM. This spatial organization of protrusion relies on myosin II contractility, and feedback between adhesion and Rac-mediated protrusive activity, such that we find Arp2/3 inhibition can promote contact guidance. Together our data support a model for contact guidance in which the ECM enforces spatial constraints on the lamellipodia that result in cell shape elongation and enforce migration direction.
authors.affiliation: Graduate Program in Biophysical Sciences, University of Chicago, Chicago, IL 60637.|Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637.|James Franck Institute, University of Chicago, Chicago, IL 60637.|Department of Physics, University of Chicago, Chicago, IL 60637.
authors.forename: G R
authors.initials: GR
authors.lastname: Ramirez-San Juan
authors.affiliation: Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637.|James Franck Institute, University of Chicago, Chicago, IL 60637.|Department of Physics, University of Chicago, Chicago, IL 60637.|Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627.|Department of Biology, University of Rochester, Rochester, NY 14627.
authors.forename: P W
authors.initials: PW
authors.lastname: Oakes
authors.affiliation: Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637 gardel@uchicago.edu.|James Franck Institute, University of Chicago, Chicago, IL 60637.|Department of Physics, University of Chicago, Chicago, IL 60637.
authors.forename: M L
authors.initials: ML
authors.lastname: Gardel
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002450:Cell Communication / Q000502:physiology; D002465:Cell Movement / Q000502:physiology*; D048430:Cell Shape / Q000502:physiology; D022081:Cell Surface Extensions / Q000378:metabolism / Q000502:physiology*; D005109:Extracellular Matrix / Q000378:metabolism / Q000502:physiology*; D005353:Fibronectins / Q000378:metabolism; D016023:Integrins / Q000378:metabolism; D051379:Mice; D024462:Myosin Type II / Q000378:metabolism; D041681:NIH 3T3 Cells; D000072458:Orientation, Spatial / Q000502:physiology*; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
chemical_list: D000199:Actins; D005353:Fibronectins; D016023:Integrins; D024462:Myosin Type II; D020830:rac1 GTP-Binding Protein