Article

Chapter 19 Mechanical Response of Cytoskeletal Networks

Department of Physics and Institute for Biophysical Dynamics, University of Chicago, Illinois 60637, USA.
Methods in cell biology (Impact Factor: 1.44). 02/2008; 89:487-519. DOI: 10.1016/S0091-679X(08)00619-5
Source: PubMed

ABSTRACT The cellular cytoskeleton is a dynamic network of filamentous proteins, consisting of filamentous actin (F-actin), microtubules, and intermediate filaments. However, these networks are not simple linear, elastic solids; they can exhibit highly nonlinear elasticity and a thermal dynamics driven by ATP-dependent processes. To build quantitative mechanical models describing complex cellular behaviors, it is necessary to understand the underlying physical principles that regulate force transmission and dynamics within these networks. In this chapter, we review our current understanding of the physics of networks of cytoskeletal proteins formed in vitro. We introduce rheology, the technique used to measure mechanical response. We discuss our current understanding of the mechanical response of F-actin networks, and how the biophysical properties of F-actin and actin cross-linking proteins can dramatically impact the network mechanical response. We discuss how incorporating dynamic and rigid microtubules into F-actin networks can affect the contours of growing microtubules and composite network rigidity. Finally, we discuss the mechanical behaviors of intermediate filaments.

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    • "In a simplified model stabilized microtubules might just be a barrier for the reorganization of actin; a disruption of MTs on the other hand gives way to an efficient, fast reorganization . This idea of MTs influencing the kinetics of the cell reorientation process was also supported by the observation that MTs may homogenize the strain distribution in in vitro actin networks and thus work as global stabilizing elements [Gardel et al., 2008]. A third possibility of how MTs influence the kinetics of cell repolarization may rely on the tight association of MTs with the f-actin network through cross-linking proteins such as spectraplakins, formins and others [Goode et al., 2000; Ishizaki et al., 2001; Kodama et al., 2003]. "
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