microfilament

Microfilaments (or actin filaments) are the thinnest filaments of the cytoskeleton, a structure found in the cytoplasm of all eukaryotic cells.

These linear polymers of actin subunits are flexible and relatively strong, resisting buckling by multi-piconewton compressive forces and filament fracture by nanonewton tensile forces. Microfilaments are highly versatile, functioning in cell crawling, amoeboid movement, and changes in cell shape. In inducing this cell motility, one end of the actin filament elongates while the other end contracts, presumably by myosin II molecular motors.