Myosin II contributes to cell-scale actin network treadmilling through network disassembly

Myosin II in cell motility In animals, most cells when on the move migrate using a crawling motion, in which the front of the cell is propelled forward by the force provided by polymerization of actin filaments. Cell biologists have generally assumed that the rear of the crawling cell is then pushed forward by a contractile force generated by non-muscle myosin II. Observations of fish keratocytes in motion now show that no actual contraction is required for rear retraction. Rather, the myosin II has a direct role in facilitating actin network treadmilling via actin disassembly.