Integration of intracellular forces
Cell motility is driven by a mechanochemical 'machine' consisting of numerous polymers of cellular protein called actin, accessory proteins and molecular motors. Actin is a globular multifunctional protein that forms intracellular scaffolds — microfilaments. Actin participates in many cellular processes, including muscle contraction, cell motility, cell division, organelle movement, cell signalling, and the establishment of cell junctions and cell shape. The mechanisms governing the assembly of the motility apparatus are still poorly understood. The EU-financed 'Biophysical aspects of actin-based motility- An integrative whole-cell analysis' (MOTILECELLBIOPHYSICS) research project is focused on investigating the biophysical aspects of the self-organisation processes underlying cell motility. Working on fish keratocytes as a model system, researchers characterised the role of the interplay between the actin cytoskeleton and the cell membrane in the motility process. They measured membrane tension in moving cells under various conditions, and showed that it is largely determined by the balance between cytoskeletal forces and the cell membrane. Importantly, membrane tension can induce mechanical coupling between processes occurring at distal locations along the cell boundary. This demonstrated that tension plays a central role in large-scale coordination of cellular dynamics. Researchers made efforts to develop artificial model systems that emulate cellular actin dynamics in a more controlled and well-defined manner. They developed a reconstituted system that self-organises into dynamic actin cortices at the inner interface of water-in-oil emulsions. In summary, the study promoted understanding of cell motility mechanisms, and the interplay between molecular processes, regulatory pathways and biophysical forces in biological self-organisation.
