MYOSIN-II LOCALIZATION DURING CYTOKINESIS OCCURS BY A MECHANISM THAT DOES NOT REQUIRE ITS MOTOR DOMAIN

Myosin II generates force for the division of eukaryotic cells. The mo lecular basis of the spatial and temporal localization of myosin II to the cleavage furrow is unknown, although models often imply that inte raction between myosin II and actin filaments is essential. We examine d the localization of a chimeric protein that consists of the green fl uorescent protein fused to the N terminus of truncated myosin II heavy chain in Dictyostelium cells. This chimera is missing the myosin II m otor domain, and it does not bind actin filaments. Surprisingly, it st ill localizes to the cleavage furrow region during cytokinesis. These results indicate that myosin II localization during cytokinesis occurs through a mechanism that does not require it to be the force-generati ng element or to interact with actin filaments directly.