title: Mechanical role of actin dynamics in the rheology of the Golgi complex and in Golgi-associated trafficking events.
abstract: BACKGROUND
  In vitro studies have shown that physical parameters, such as membrane curvature, tension, and composition, influence the budding and fission of transport intermediates. Endocytosis in living cells also appears to be regulated by the mechanical load experienced by the plasma membrane. In contrast, how these parameters affect intracellular membrane trafficking in living cells is not known. To address this question, we investigate here the impact of a mechanical stress on the organization of the Golgi complex and on the formation of transport intermediates from the Golgi complex.
  
  
  RESULTS
  Using confocal microscopy, we visualize the deformation of Rab6-positive Golgi membranes applied by an internalized microsphere trapped in optical tweezers and simultaneously measure the corresponding forces. Our results show that the force necessary to deform Golgi membranes drops when actin dynamics is altered and correlates with myosin II activity. We also show that the applied stress has a long-range effect on Golgi membranes, perturbs the dynamics of Golgi-associated actin, and induces a sharp decrease in the formation of Rab6-positive vesicles from the Golgi complex as well as tubulation of Golgi membranes.
  
  
  CONCLUSIONS
  We suggest that acto-myosin contractility strongly contributes to the local rigidity of the Golgi complex and regulates the mechanics of the Golgi complex to control intracellular membrane trafficking.
authors.affiliation: CNRS-Institut Curie, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: David
authors.initials: D
authors.lastname: Guet
authors.affiliation: CNRS-Institut Curie, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Kalpana
authors.initials: K
authors.lastname: Mandal
authors.affiliation: CNRS-Institut Curie, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Pinot
authors.affiliation: CNRS-Institut Curie, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Jessica
authors.initials: J
authors.lastname: Hoffmann
authors.affiliation: CNRS-Institut Curie, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Yara
authors.initials: Y
authors.lastname: Abidine
authors.affiliation: CNRS-Institut Curie, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Walter
authors.initials: W
authors.lastname: Sigaut
authors.affiliation: CNRS-Institut Curie, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Sabine
authors.initials: S
authors.lastname: Bardin
authors.affiliation: CNRS-Institut Curie, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Kristine
authors.initials: K
authors.lastname: Schauer
authors.affiliation: CNRS-Institut Curie, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France. Electronic address: bruno.goud@curie.fr.
authors.forename: Bruno
authors.initials: B
authors.lastname: Goud
authors.affiliation: CNRS-Institut Curie, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France. Electronic address: jean-baptiste.manneville@curie.fr.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Manneville
mesh_terms: D000199:Actins / Q000378:metabolism; D001696:Biomechanical Phenomena; D002478:Cells, Cultured; D006056:Golgi Apparatus / Q000378:metabolism*; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D018613:Microscopy, Confocal; D024462:Myosin Type II / Q000378:metabolism; D012212:Rheology; D020691:rab GTP-Binding Proteins / Q000378:metabolism
chemical_list: D000199:Actins; C094135:Rab6 protein; D024462:Myosin Type II; D020691:rab GTP-Binding Proteins