A Quantitative Analysis of Contractility in Active Cytoskeletal Protein Networks

@article{citeulike:2674004, abstract = {Cells actively produce contractile forces for a variety of processes including cytokinesis and motility. Contractility is known to rely on myosin II motors which convert chemical energy from ATP hydrolysis into forces on actin filaments. However, the basic physical principles of cell contractility remain poorly understood. We reconstitute contractility in a simplified model system of purified F-actin, muscle myosin II motors, and{alpha} -actinin cross-linkers. We show that contractility occurs above a threshold motor concentration and within a window of cross-linker concentrations. We also quantify the pore size of the bundled networks and find contractility to occur at a critical distance between the bundles. We propose a simple mechanism of contraction based on myosin filaments pulling neighboring bundles together into an aggregated structure. Observations of this reconstituted system in both bulk and low-dimensional geometries show that the contracting gels pull on and deform their surface with a contractile force of [~]1 {micro}N, or [~]100 pN per F-actin bundle. Cytoplasmic extracts contracting in identical environments show a similar behavior and dependence on myosin as the reconstituted system. Our results suggest that cellular contractility can be sensitively regulated by tuning the (local) activity of molecular motors and the cross-linker density and binding affinity. 10.1529/biophysj.107.117960}, author = {Bendix, Poul M. and Koenderink, Gijsje H. and Cuvelier, Damien and Dogic, Zvonimir and Koeleman, Bernard N. and Brieher, William M. and Field, Christine M. and Mahadevan, L. and Weitz, David A. }, citeulike-article-id = {2674004}, doi = {10.1529/biophysj.107.117960}, journal = {Biophys. J.}, keywords = {complex, contractile}, month = {April}, number = {8}, pages = {3126--3136}, posted-at = {2008-04-15 17:34:17}, priority = {2}, title = {A Quantitative Analysis of Contractility in Active Cytoskeletal Protein Networks}, url = {http://dx.doi.org/10.1529/biophysj.107.117960}, volume = {94}, year = {2008} }

TY - JOUR ID - citeulike:2674004 L3 - citeulike-article-id:2674004 TI - A Quantitative Analysis of Contractility in Active Cytoskeletal Protein Networks JF - Biophys. J. VL - 94 IS - 8 SP - 3126 EP - 3136 N2 - Cells actively produce contractile forces for a variety of processes including cytokinesis and motility. Contractility is known to rely on myosin II motors which convert chemical energy from ATP hydrolysis into forces on actin filaments. However, the basic physical principles of cell contractility remain poorly understood. We reconstitute contractility in a simplified model system of purified F-actin, muscle myosin II motors, and{alpha} -actinin cross-linkers. We show that contractility occurs above a threshold motor concentration and within a window of cross-linker concentrations. We also quantify the pore size of the bundled networks and find contractility to occur at a critical distance between the bundles. We propose a simple mechanism of contraction based on myosin filaments pulling neighboring bundles together into an aggregated structure. Observations of this reconstituted system in both bulk and low-dimensional geometries show that the contracting gels pull on and deform their surface with a contractile force of [~]1 {micro}N, or [~]100 pN per F-actin bundle. Cytoplasmic extracts contracting in identical environments show a similar behavior and dependence on myosin as the reconstituted system. Our results suggest that cellular contractility can be sensitively regulated by tuning the (local) activity of molecular motors and the cross-linker density and binding affinity. 10.1529/biophysj.107.117960 KW - complex KW - contractile AU - Bendix, Poul AU - Koenderink, Gijsje AU - Cuvelier, Damien AU - Dogic, Zvonimir AU - Koeleman, Bernard AU - Brieher, William AU - Field, Christine AU - Mahadevan, L AU - Weitz, David PY - 2008/04/15/ UR - http://dx.doi.org/10.1529/biophysj.107.117960 ER -