Constriction of the cytokinetic ring, a circular structure of actin filaments, is an essential step during cell division. Mechanical forces driving the constriction are attributed to myosin motor proteins, which slide actin filaments along each other. However, in multiple organisms, ring constriction has been reported to be myosin independent. How actin rings constrict in the absence of motor activity remains unclear. Here, we demonstrate that anillin, a non-motor actin crosslinker, indispensable during cytokinesis, autonomously propels the contractility of actin bundles. Anillin generates contractile forces of tens of pico-Newtons to maximise the lengths of overlaps between bundled actin filaments. The contractility is enhanced by actin disassembly. When multiple actin filaments are arranged into a ring, this contractility leads to ring constriction. Our results indicate that passive actin crosslinkers can substitute for the activity of molecular motors to generate contractile forces in a variety of actin networks, including the cytokinetic ring.

• MeSH
• Actins metabolism   MeSH
• Actomyosin metabolism   MeSH
• Cell Division MeSH
• Cytokinesis MeSH
• Drosophila melanogaster metabolism   MeSH
• Contractile Proteins genetics   metabolism   MeSH
• Humans MeSH
• Actin Cytoskeleton metabolism   MeSH
• Microfilament Proteins MeSH
• Myosins metabolism   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Actins MeSH
• Actomyosin MeSH
• anillin MeSH Browser
• ANLN protein, human MeSH Browser
• Contractile Proteins MeSH
• Microfilament Proteins MeSH
• Myosins MeSH