FIGURE 1:

Mechanobiology and migration. Schematic of cells migrating on two-dimensional (2D) or 3D matrices. The 2D example shows the principles of mechanobiology by which a cell reads (green arrows) the mechanical properties of the ECM and converts them into a biochemical intracellular signal (red arrow) that affects the cytoskeleton, signaling, and transcription. Ultimately, the cell responds both by applying forces to the matrix itself (blue arrow) and undergoing processes such as proliferation, apoptosis, differentiation, and migration (large blue arrow). Mechanosensing occurs as the cells interact with the ECM through focal adhesions (green), which are linked to actin fibers (pink). The situation is more complicated in 3D migration, in which cells can move inside a matrix, here composed of fibers (different shades of orange) of different composition, structure, topology, and rigidity and other nonmigrating cells (pink). The drawing shows both a single invading cell (pink), moving in the direction of the arrow, and a group of migrating cells (pink) moving collectively and attached to one another by cell–cell junctions (magenta). Attached to the group of cells there can also be nonmigrating, nonpolarized cells (brown). In this complex situation, cells must integrate the signals transmitted by different types of focal adhesions and adherens junctions.