Myosin is a type of protein that plays a crucial role in muscle contraction and movement in cells. It works by interacting with another protein called actin, forming structures known as filaments. When myosin heads attach to actin, they pull on the filaments, causing the muscle fibers to shorten and contract. In addition to muscle cells, myosin is also found in various types of cells throughout the body, where it helps with processes like cell division and transport of materials within the cell. This makes myosin essential for many biological functions beyond just movement.