Actin Filaments (Microfilaments)

Actin filaments(otherwise known as microfilaments) are made up of the protein actin and are helical polymers. They appear as flexible structures, with a diameter of about 7 nanometers, that are arranged into a variety of linear bundles, two-dimensional networks, and three-dimensional gels. Although actin filaments are dispersed throughout the cell, they are most highly concentrated in the cortex, just beneath the plasma membrane.