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Takito J, Inoue S, Nakamura M. The Sealing Zone in Osteoclasts: A Self-Organized Structure on the Bone. Int J Mol Sci 2018; 19:E984. [PMID: 29587415 DOI: 10.3390/ijms19040984] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/22/2018] [Accepted: 03/23/2018] [Indexed: 01/08/2023] Open
Abstract
Osteoclasts form a specialized cell-matrix adhesion structure, known as the "sealing zone", during bone resorption. The sealing zone is a dynamic actin-rich structure that defines the resorption area of the bone. The detailed dynamics and fine structure of the sealing zone have been elusive. Osteoclasts plated on glass do not form a sealing zone, but generate a separate supra-molecular structure called the "podosome belt". Podosomes are integrin-based adhesion complexes involved in matrix adhesion, cell migration, matrix degradation, and mechanosensing. Invadopodia, podosome-like protrusions in cancer cells, are involved in cell invasion into other tissues by promoting matrix degradation. Both podosomes and invadopodia exhibit actin pattern transitions during maturation. We previously found that Arp2/3-dependent actin flow occurs in all observed assembly patterns of podosomes in osteoclasts on glass. It is known that the actin wave in Dictyostelium cells exhibits a similar pattern transition in its evolution. Because of significant advances in our understanding regarding the mechanism of podosomes/invadopodia formation over the last decade, we revisited the structure and function of the sealing zone in this review, highlighting the possible involvement of self-organized actin waves in the organogenesis of the sealing zone.
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Tomba C, Braïni C, Bugnicourt G, Cohen F, Friedrich BM, Gov NS, Villard C. Geometrical Determinants of Neuronal Actin Waves. Front Cell Neurosci 2017; 11:86. [PMID: 28424590 PMCID: PMC5372798 DOI: 10.3389/fncel.2017.00086] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/13/2017] [Indexed: 11/19/2022] Open
Abstract
Hippocampal neurons produce in their early stages of growth propagative, actin-rich dynamical structures called actin waves. The directional motion of actin waves from the soma to the tip of neuronal extensions has been associated with net forward growth, and ultimately with the specification of neurites into axon and dendrites. Here, geometrical cues are used to control actin wave dynamics by constraining neurons on adhesive stripes of various widths. A key observable, the average time between the production of consecutive actin waves, or mean inter-wave interval (IWI), was identified. It scales with the neurite width, and more precisely with the width of the proximal segment close to the soma. In addition, the IWI is independent of the total number of neurites. These two results suggest a mechanistic model of actin wave production, by which the material conveyed by actin waves is assembled in the soma until it reaches the threshold leading to the initiation and propagation of a new actin wave. Based on these observations, we formulate a predictive theoretical description of actin wave-driven neuronal growth and polarization, which consistently accounts for different sets of experiments.
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Affiliation(s)
- Caterina Tomba
- Université Grenoble Alpes, Centre National de la Recherche Scientifique (CNRS), Institut NéelGrenoble, France.,Université Grenoble Alpes, Centre National de la Recherche Scientifique (CNRS), Laboratoire des Technologies de la Microélectronique, CEA-LETIGrenoble, France
| | - Céline Braïni
- Université Grenoble Alpes, Centre National de la Recherche Scientifique (CNRS), Institut NéelGrenoble, France.,Laboratoire PhysicoChimie Curie, Institut Curie, Pierre-Gilles de Gennes Institute for Microfluidics, CNRS, PSL Research UniversityParis, France
| | - Ghislain Bugnicourt
- Université Grenoble Alpes, Centre National de la Recherche Scientifique (CNRS), Institut NéelGrenoble, France
| | - Floriane Cohen
- Laboratoire PhysicoChimie Curie, Institut Curie, Pierre-Gilles de Gennes Institute for Microfluidics, CNRS, PSL Research UniversityParis, France
| | - Benjamin M Friedrich
- Biological Algorithms Group, Center for Advancing Electronics Dresden, Technische Universität DresdenDresden, Germany
| | - Nir S Gov
- Department of Chemical Physics, Weizmann Institute of ScienceRehovot, Israel
| | - Catherine Villard
- Université Grenoble Alpes, Centre National de la Recherche Scientifique (CNRS), Institut NéelGrenoble, France.,Laboratoire PhysicoChimie Curie, Institut Curie, Pierre-Gilles de Gennes Institute for Microfluidics, CNRS, PSL Research UniversityParis, France
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