A free-boundary model of a motile cell explains turning behavior
| Autor: | Alex Mogilner, Aaron Rumack, Stephanie Pulford, Masoud Nickaeen, Igor L. Novak, Jamie Brandon, Boris M. Slepchenko |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Velocity Microfilament Biochemistry Contractile Proteins Cell Movement Myosin Membrane Technology Pseudopodia lcsh:QH301-705.5 Ecology Simulation and Modeling Physics Classical Mechanics Built Structures Biomechanical Phenomena Cell biology Cell Motility Aspect Ratio Computational Theory and Mathematics Cell Processes Modeling and Simulation Physical Sciences Engineering and Technology Lamellipodium Axial symmetry Research Article Structural Engineering Motor Proteins Actin Motors Geometry Motility macromolecular substances Myosins Biology Research and Analysis Methods Membrane Structures Contractility Motion 03 medical and health sciences Cellular and Molecular Neuroscience Molecular Motors Genetics Cell Shape Molecular Biology Ecology Evolution Behavior and Systematics Actin Isotropy Biology and Life Sciences Proteins Cell Biology Models Theoretical Actins Cytoskeletal Proteins 030104 developmental biology lcsh:Biology (General) Biophysics Mathematics Actin Polymerization |
| Zdroj: | PLoS Computational Biology, Vol 13, Iss 11, p e1005862 (2017) PLoS Computational Biology |
| ISSN: | 1553-7358 |
| Popis: | To understand shapes and movements of cells undergoing lamellipodial motility, we systematically explore minimal free-boundary models of actin-myosin contractility consisting of the force-balance and myosin transport equations. The models account for isotropic contraction proportional to myosin density, viscous stresses in the actin network, and constant-strength viscous-like adhesion. The contraction generates a spatially graded centripetal actin flow, which in turn reinforces the contraction via myosin redistribution and causes retraction of the lamellipodial boundary. Actin protrusion at the boundary counters the retraction, and the balance of the protrusion and retraction shapes the lamellipodium. The model analysis shows that initiation of motility critically depends on three dimensionless parameter combinations, which represent myosin-dependent contractility, a characteristic viscosity-adhesion length, and a rate of actin protrusion. When the contractility is sufficiently strong, cells break symmetry and move steadily along either straight or circular trajectories, and the motile behavior is sensitive to conditions at the cell boundary. Scanning of a model parameter space shows that the contractile mechanism of motility supports robust cell turning in conditions where short viscosity-adhesion lengths and fast protrusion cause an accumulation of myosin in a small region at the cell rear, destabilizing the axial symmetry of a moving cell. Author summary To understand shapes and movements of simple motile cells, we systematically explore minimal models describing a cell as a two-dimensional actin-myosin gel with a free boundary. The models account for actin-myosin contraction balanced by viscous stresses in the actin gel and uniform adhesion. The myosin contraction causes the lamellipodial boundary to retract. Actin protrusion at the boundary counters the retraction, and the balance of protrusion and retraction shapes the cell. The models reproduce a variety of motile shapes observed experimentally. The analysis shows that the mechanical state of a cell depends on a small number of parameters. We find that when the contractility is sufficiently strong, cells break symmetry and move steadily along either straight or circular trajectory. Scanning model parameters shows that the contractile mechanism of motility supports robust cell turning behavior in conditions where deformable actin gel and fast protrusion destabilize the axial symmetry of a moving cell. |
| Databáze: | OpenAIRE |
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