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Assembly and positioning of actomyosin rings by contractility and planar cell polarity.

Sehring IM, Recho P, Denker E, Kourakis M, Mathiesen B, Hannezo E, Dong B, Jiang D - Elife (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.

ABSTRACT
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.

No MeSH data available.


Robustness of the anterior and posterior fronts dynamics and average filament velocity during the ring migration in control case with .DOI:http://dx.doi.org/10.7554/eLife.09206.024
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fig15: Robustness of the anterior and posterior fronts dynamics and average filament velocity during the ring migration in control case with .DOI:http://dx.doi.org/10.7554/eLife.09206.024

Mentions: If we suppose that is less than leading to the condition where α < 1, we show below the effect of a small deviation α = 0.95. See Appendix figure 8. While the anterior and posterior dynamics is still correctly captured, the agreement of the average filament velocity is not good any more even though the order of magnitude is still correct. The system is thus sensitive to this condition. However, if the condition is modified by assuming a certain value of α, by changing other parameters of the model, we can still obtain a good agreement with the experimental data. What this analysis suggests, if the model is correct, is that a change of externally applied tension would strongly affect the internal cortical flow, a fact which awaits experimental verification in the present setting.10.7554/eLife.09206.024Appendix figure 8.Robustness of the anterior and posterior fronts dynamics and average filament velocity during the ring migration in control case with .


Assembly and positioning of actomyosin rings by contractility and planar cell polarity.

Sehring IM, Recho P, Denker E, Kourakis M, Mathiesen B, Hannezo E, Dong B, Jiang D - Elife (2015)

Robustness of the anterior and posterior fronts dynamics and average filament velocity during the ring migration in control case with .DOI:http://dx.doi.org/10.7554/eLife.09206.024
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4612727&req=5

fig15: Robustness of the anterior and posterior fronts dynamics and average filament velocity during the ring migration in control case with .DOI:http://dx.doi.org/10.7554/eLife.09206.024
Mentions: If we suppose that is less than leading to the condition where α < 1, we show below the effect of a small deviation α = 0.95. See Appendix figure 8. While the anterior and posterior dynamics is still correctly captured, the agreement of the average filament velocity is not good any more even though the order of magnitude is still correct. The system is thus sensitive to this condition. However, if the condition is modified by assuming a certain value of α, by changing other parameters of the model, we can still obtain a good agreement with the experimental data. What this analysis suggests, if the model is correct, is that a change of externally applied tension would strongly affect the internal cortical flow, a fact which awaits experimental verification in the present setting.10.7554/eLife.09206.024Appendix figure 8.Robustness of the anterior and posterior fronts dynamics and average filament velocity during the ring migration in control case with .

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.

ABSTRACT
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.

No MeSH data available.