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. 2005 Sep;89(3):1643-9.
doi: 10.1529/biophysj.105.066720. Epub 2005 Jul 8.

Lamellipodial contractions during crawling and spreading

Charles W Wolgemuth  1
Affiliations

Lamellipodial contractions during crawling and spreading

Charles W Wolgemuth. Biophys J. 2005 Sep.

Erratum in

  • Biophys J. 2006 Jan 15;90(2):708

Abstract

Most eukaryotic cells can crawl over surfaces. In general, this motility requires three distinct actions: polymerization at the leading edge, adhesion to the substrate, and retraction at the rear. Recent experiments with mouse embryonic fibroblasts showed that during spreading and crawling the lamellipodium undergoes periodic contractions that are substrate-dependent. Here I show that a simple model incorporating stick-slip adhesion and a simplified mechanism for the generation of contractile forces is sufficient to explain periodic lamellipodial contractions. This model also explains why treatment of cells with latrunculin modifies the period of these contractions. In addition, by coupling a diffusing chemical species that can bind actin, such as myosin light-chain kinase, with the contractile model leads to periodic rows and waves in the chemical species, similar to what is observed in experiments. This model provides a novel and simple explanation for the generation of contractile waves during cell spreading and crawling that is only dependent on stick-slip adhesion and the generation of contractile force and suggests new experiments to test this mechanism.

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Figures

FIGURE 1
FIGURE 1
Schematic of the model. (a) The migrating cell is composed of two regions, the lamellipodium and the lamella. The lamellipodium is weakly attached to the substrate and directly in front of the lamella, which is attached to the substrate through firm adhesions. (b) Polymerization at the front of the cell pushes the leading edge forward, whereas depolymerization of the network induces contractile stress in the lamellipod. (c) When sufficient stress has been generated, the weak adhesions can break (d), leading to contraction of the leading edge.
FIGURE 2
FIGURE 2
Leading-edge position in arbitrary units as a function of time for three different values of (a) the slipping force, Vslip: σ0Vslip/ζL0 = 0.4 (solid), σ0Vslip/ζL0 = 0.3 (dashed), and σ0Vslip/ζL0 = 0.2 (dotted), with formula image and σ0Vf/ζL0 = 0.1; (b) the ratio of the polymerization velocity, Vf, to the slipping velocity, Vslip: Vf/Vslip = 1.75 (solid), Vf/Vslip = 1.0 (dashed), and Vf/Vslip = 0.78 (dotted), with formula image and Vslip: σ0Vf/ζL0 = 0.14; and (c) the decay rate γ: formula image (solid), formula image (dashed), and formula image (dotted), with σ0Vslip/ζL0 = 0.32 and σ0Vf/ζL0 = 0.1.
FIGURE 3
FIGURE 3
Effect of increased depolymerization on the lamellipod. Plot of contraction period, T, versus the lamellipodial width, L/L0. For smaller widths, the period is linearly proportional to the width (solid line shows linear fit). (Inset) Dependence of lamellipodial width on the decay rate, γ.
FIGURE 4
FIGURE 4
Contractions produce rearward traveling periodic waves and rows in the concentration of actin-binding proteins at the rear of the lamellipod. (a) Schematic showing how contractions and advance of the lamellar adhesions “lock in” periodic variations in the concentration. The top view shows a spreading cell at two times. The dotted rectangles represent a slice of the cell used to generate a kymograph. The side view shows the actin-binding protein concentration inside the cell during a contraction. (b) Kymograph of the concentration of actin-binding proteins obtained from stacking the one-dimensional simulation results of the solution to Eq. 2 with formula image and σ0Vslip/ζL0 = 0.32 showing rearward traveling waves in the concentration (solid arrowheads). (c) Concentration of actin-binding protein as a function of position in the lamellipod. The periodic waves produce rows of high concentration at the rear of the lamellipod.
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References

    1. Abercrombie, M. 1980. The Croonian lecture, 1978. The crawling movement of metazoan cells. Proc. R. Soc. Lond. B. Biol. Sci. 207:129–147.
    1. Lauffenburger, D. A., and A. F. Horwitz. 1996. Cell migration: a physically integrated molecular process. Cell. 84:359–369. - PubMed
    1. Mitchison, T. J., and L. P. Cramer. 1996. Actin-based cell motility and cell locomotion. Cell. 84:371–379. - PubMed
    1. Peskin, C., G. Odell, and G. Oster. 1993. Cellular motions and thermal fluctuations: the Brownian ratchet. Biophys. J. 65:316–324. - PMC - PubMed
    1. Mogilner, A., and G. Oster. 2003. Force generation by actin polymerization II: the elastic ratchet and tethered filaments. Biophys. J. 84:1591–1605. - PMC - PubMed

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