Portal de Periódicos da CAPES

Actin cortex mechanics and cellular morphogenesis

2012; Elsevier BV; Volume: 22; Issue: 10 Linguagem: Inglês

10.1016/j.tcb.2012.07.001

1879-3088

Guillaume Salbreux, Guillaume Charras, Ewa K. Paluch,

3D Printing in Biomedical Research

The cortex is a thin, crosslinked actin network lying immediately beneath the plasma membrane of animal cells. Myosin motors exert contractile forces in the meshwork. Because the cortex is attached to the cell membrane, it plays a central role in cell shape control. The proteic constituents of the cortex undergo rapid turnover, making the cortex both mechanically rigid and highly plastic, two properties essential to its function. The cortex has recently attracted increasing attention and its functions in cellular processes such as cytokinesis, cell migration, and embryogenesis are progressively being dissected. In this review, we summarize current knowledge on the structural organization, composition, and mechanics of the actin cortex, focusing on the link between molecular processes and macroscopic physical properties. We also highlight consequences of cortex dysfunction in disease. The cortex is a thin, crosslinked actin network lying immediately beneath the plasma membrane of animal cells. Myosin motors exert contractile forces in the meshwork. Because the cortex is attached to the cell membrane, it plays a central role in cell shape control. The proteic constituents of the cortex undergo rapid turnover, making the cortex both mechanically rigid and highly plastic, two properties essential to its function. The cortex has recently attracted increasing attention and its functions in cellular processes such as cytokinesis, cell migration, and embryogenesis are progressively being dissected. In this review, we summarize current knowledge on the structural organization, composition, and mechanics of the actin cortex, focusing on the link between molecular processes and macroscopic physical properties. We also highlight consequences of cortex dysfunction in disease. force per unit length exerted on a piece of the cortex by the cortical network around it (Figure 2a). A local increase in cortical tension energetically favors a local decrease in surface area. the fraction of time spent by a molecular motor attached to its filament during one motor cycle. owing to thermal fluctuations, a polymer in solution can bend and adopt a more or less convoluted shape, depending on its bending rigidity. As a result, the correlation between two unit vectors tangential to the filament at two points on the filament decays as the distance between the two points increases. The characteristic length of the decay is the persistence length of the filament. coefficient characterizing the response of an object to deformation. Stiffness is defined as the ratio between the force exerted on the object and the deformation induced by this force. By contrast to the elastic modulus, which is an intrinsic property of a material, stiffness is an effective property of an object and can depend on various physical parameters, including tension and elasticity (Box 2). property of a material displaying rheological properties characteristic of both elastic solids and liquids on deformation. In Kelvin–Voigt viscoelastic materials (which are viscous at short timescales and elastic at long timescales) or Maxwell viscoelastic materials (which are elastic at short timescales and viscous at long timescales) the transition from one behavior to the other occurs on a characteristic timescale called the viscoelastic relaxation time. Biological networks are usually elastic on short timescales and viscous on long timescales because of turnover and remodeling.