Assembly and positioning of actomyosin rings by contractility and planar cell polarity
Ivonne M Sehring,
Pierre Recho,
Elsa Denker,
Matthew Kourakis,
Birthe Mathiesen,
Edouard Hannezo,
Bo Dong,
Di Jiang
Affiliations
Ivonne M Sehring
Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
Pierre Recho
Department of Physico-Chemistry of Living Matter, Institut Curie, Paris, France; Mathematical Institute, University of Oxford, Oxford, United Kingdom
Elsa Denker
Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
Matthew Kourakis
Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States
Birthe Mathiesen
Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
Edouard Hannezo
Department of Physico-Chemistry of Living Matter, Institut Curie, Paris, France; The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom
Bo Dong
Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology
Di Jiang
Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
The actomyosin cytoskeleton is a primary force-generating mechanism in morphogenesis, thus a robust spatial control of cytoskeletal positioning is essential. In this report, we demonstrate that actomyosin contractility and planar cell polarity (PCP) interact in post-mitotic Ciona notochord cells to self-assemble and reposition actomyosin rings, which play an essential role for cell elongation. Intriguingly, rings always form at the cells′ anterior edge before migrating towards the center as contractility increases, reflecting a novel dynamical property of the cortex. Our drug and genetic manipulations uncover a tug-of-war between contractility, which localizes cortical flows toward the equator and PCP, which tries to reposition them. We develop a simple model of the physical forces underlying this tug-of-war, which quantitatively reproduces our results. We thus propose a quantitative framework for dissecting the relative contribution of contractility and PCP to the self-assembly and repositioning of cytoskeletal structures, which should be applicable to other morphogenetic events.
