Strain field in actin filament network in lamellipodia of migrating cells: Implication for network reorganization

Adachi, Taiji; Okeyo, Kennedy Omondi; Shitagawa, Yoshimichi; Hojo, Masaki

doi:10.1016/j.jbiomech.2008.11.012

Cited by 30 publications

(39 citation statements)

References 37 publications

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“…Black tetra keratocytes used in this study were cultured and handled essentially as described previously (Adachi et al, 2009). After isolation, freely moving keratocytes were microinjected with an 8 mM conjugate solution of quantum dot-phalloidin (Qdot-phalloidin) and incubated for 30 min before use.…”

Section: Cell Culture and Actomyosin Perturbationmentioning

confidence: 99%

“…Moreover, information from F-actin network flow can be utilized to define the mechanical properties of the network, and even how it interacts with other components like myosin II or focal adhesion proteins (Ji et al, 2008). Previously, a quantitative study using FSM and image intensity correlation evaluated the strain field in the lamellipodial F-actin network and proposed the selective depolymerization model to correlate negative strain with network depolymerization (Adachi et al, 2009). Since the cytoskeleton is a complex system whose dynamics involves various interacting components, systematic perturbation of the actomyosin machinery is considered a suitable method for elucidating the relationship between actomyosinbased force generation and F-actin dynamics.…”

Section: Introductionmentioning

confidence: 99%

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Actomyosin contractility spatiotemporally regulates actin network dynamics in migrating cells

Okeyo

Adachi

Sunaga

et al. 2009

Journal of Biomechanics

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Section: Cell Culture and Actomyosin Perturbationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Actomyosin contractility spatiotemporally regulates actin network dynamics in migrating cells

Okeyo

Adachi

Sunaga

et al. 2009

Journal of Biomechanics

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“…These cells are known for their rapid locomotion and simple shape, making them an ideal systems for investigating cell migration. 1,42 First, we investigated lamellipodial protrusion on a micropattern with wide intercalated gaps (d = 9 lm), such as the one shown in Fig. 2a.…”

Section: Lamellipodial Extension Is Affected By Actomyosin Contractilitymentioning

confidence: 99%

Effect of Actomyosin Contractility on Lamellipodial Protrusion Dynamics on a Micropatterned Substrate

et al. 2011

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Actin polymerization-driven protrusion of the lamellipodia is a requisite initial step during actin-based cell migration, and is closely associated with attachment to the substrate. Although tremendous progress has been made in recent years toward elucidating the molecular details of focal adhesions, our understanding of the basic coordination of protrusion and adhesion, and how the two fundamental processes relate to actomyosin contractility is still inadequate. Therefore, to highlight the effect of cell-substrate interactions on the protrusive dynamics of the lamellipodia and to correlate protrusion with actomyosin activities, this study investigated the migration of fish epidermal keratocytes on fibronectin micropatterns intercalated with adhesionsuppressed gaps of varying widths. We show that insufficient adhesion associated with the gaps could limit lamellipodial protrusion such that the percentage of migrating cells decreases with an increase in gap width, and protrusion across the gaps is accompanied by ruffling. Moreover, our results suggest that up-regulating actomyosin contractility enhances the mechanical integrity of the actin cytoskeleton, leading to an increase in the width of the lamellipodia, and consequently, an increase in the percentage of cells migrating across the gaps. Thus, we demonstrate that the protrusion dynamics at the leading edge of migrating cells are functionally involved in the global mechanical regulation of actin cytoskeletal components that enable cell migration.

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“…The lamellipodia is a few hundred nanometers thick but several tens of micrometers wide and about ten micrometers long. Because a keratocyte is thinner than the broad lamellipodia, we focus on the cross-sectional shape across the normal to the substrate, as many previous experimental and theoretical studies have done (Mogilner and Oster 1996;Mogilner and Edelstein-Keshet 2002;Grimm et al 2003;Ponti et al 2004;Satyanarayana and Baumgaertner 2004;Rubinstein et al 2005;Marée et al 2006;Lacayo et al 2007;Keren et al 2008;Adachi et al 2009). …”

Section: Cellular-scale Model Of Migrating Keratocytesmentioning

confidence: 99%

“…3, respectively. Black tetra keratocytes used in this study were cultured and handled essentially as described previously (Adachi et al 2009). Isolated, freely moving keratocytes were fixed with 5% paraformaldehyde, permeabilized with 0.2% Triton-X, and then incubated for 150 min at 37 • C with 25nM rhodamine-phalloidin (Invitrogen) diluted in PBS for F-actin staining.…”

Section: Conditionmentioning

confidence: 99%

Coarse-grained Brownian ratchet model of membrane protrusion on cellular scale

Inoue

Adachi

2010

Biomech Model Mechanobiol

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Membrane protrusion is a mechanochemical process of active membrane deformation driven by actin polymerization. Previously, Brownian ratchet (BR) was modeled on the basis of the underlying molecular mechanism. However, because the BR requires a priori load that cannot be determined without information of the cell shape, it cannot be effective in studies in which resultant shapes are to be solved. Other cellular-scale models describing the protrusion have also been suggested for modeling a whole cell; however, these models were not developed on the basis of coarse-grained physics representing the underlying molecular mechanism. Therefore, to express the membrane protrusion on the cellular scale, we propose a novel mathematical model, the coarse-grained BR (CBR), which is derived on the basis of nonequilibrium thermodynamics theory. The CBR can reproduce the BR within the limit of the quasistatic process of membrane protrusion and can estimate the protrusion velocity consistently with an effective elastic constant that represents the state of the energy of the membrane. Finally, to demonstrate the applicability of the CBR, we attempt to perform a cellular-scale simulation of migrating keratocyte in which the proposed CBR is used for the membrane protrusion model on the cellular scale. The results show that the experimentally observed shapes of the leading edge are well reproduced by the simulation. In addition, The trend of dependences of the protrusion velocity on the curvature of the leading edge, the temperature, and the substrate stiffness also agreed with the other experimental results. Thus, the CBR can be considered an appropriate cellular-scale model to express the membrane protrusion on the basis of its underlying molecular mechanism.

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Strain field in actin filament network in lamellipodia of migrating cells: Implication for network reorganization

Cited by 30 publications

References 37 publications

Actomyosin contractility spatiotemporally regulates actin network dynamics in migrating cells

Actomyosin contractility spatiotemporally regulates actin network dynamics in migrating cells

Effect of Actomyosin Contractility on Lamellipodial Protrusion Dynamics on a Micropatterned Substrate

Coarse-grained Brownian ratchet model of membrane protrusion on cellular scale

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