title: Architecture and Connectivity Govern Actin Network Contractility.
abstract: Actomyosin contractility plays a central role in a wide range of cellular processes, including the establishment of cell polarity, cell migration, tissue integrity, and morphogenesis during development. The contractile response is variable and depends on actomyosin network architecture and biochemical composition. To determine how this coupling regulates actomyosin-driven contraction, we used a micropatterning method that enables the spatial control of actin assembly. We generated a variety of actin templates and measured how defined actin structures respond to myosin-induced forces. We found that the same actin filament crosslinkers either enhance or inhibit the contractility of a network, depending on the organization of actin within the network. Numerical simulations unified the roles of actin filament branching and crosslinking during actomyosin contraction. Specifically, we introduce the concept of "network connectivity" and show that the contractions of distinct actin architectures are described by the same master curve when considering their degree of connectivity. This makes it possible to predict the dynamic response of defined actin structures to transient changes in connectivity. We propose that, depending on the connectivity and the architecture, network contraction is dominated by either sarcomeric-like or buckling mechanisms. More generally, this study reveals how actin network contractility depends on its architecture under a defined set of biochemical conditions.
authors.affiliation: Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire et Vegétale, CNRS/CEA/UGA/INRA, Grenoble 38054, France.
authors.forename: Hajer
authors.initials: H
authors.lastname: Ennomani
authors.affiliation: Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire et Vegétale, CNRS/CEA/UGA/INRA, Grenoble 38054, France.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Letort
authors.affiliation: Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire et Vegétale, CNRS/CEA/UGA/INRA, Grenoble 38054, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Guérin
authors.affiliation: Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire et Vegétale, CNRS/CEA/UGA/INRA, Grenoble 38054, France.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Martiel
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, CT 06520-8114, USA.
authors.forename: Wenxiang
authors.initials: W
authors.lastname: Cao
authors.affiliation: Cell Biology and Biophysics Unit, EMBL, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
authors.forename: François
authors.initials: F
authors.lastname: Nédélec
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, CT 06520-8114, USA.
authors.forename: Enrique M
authors.initials: EM
authors.lastname: De La Cruz
authors.affiliation: Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire et Vegétale, CNRS/CEA/UGA/INRA, Grenoble 38054, France; Unité de thérapie Cellulaire, Hopital Saint-Louis, Avenue Claude Vellefaux, Paris 75010, France. Electronic address: manuel.thery@cea.fr.
authors.forename: Manuel
authors.initials: M
authors.lastname: Théry
authors.affiliation: Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire et Vegétale, CNRS/CEA/UGA/INRA, Grenoble 38054, France. Electronic address: laurent.blanchoin@cea.fr.
authors.forename: Laurent
authors.initials: L
authors.lastname: Blanchoin
mesh_terms: D000199:Actins / Q000378:metabolism*; D000205:Actomyosin / Q000378:metabolism*; D000818:Animals; D009119:Muscle Contraction; D009218:Myosins / Q000378:metabolism*; D011817:Rabbits
chemical_list: D000199:Actins; D000205:Actomyosin; D009218:Myosins