title: Animal cell division: a fellowship of the double ring?
abstract: Despite a century of research into the nature of animal cell division, a molecular explanation for the positioning of the actomyosin contractile ring has remained elusive. The discovery of a novel interaction between regulators of Rho family small GTPases has revealed a link between the mitotic microtubules and the contractile ring during the later stages of mitosis. The properties of the interacting Rho regulators suggest a molecular model for the positioning and initiation of contractile ring furrowing in animal cells. In this 'double ring' model, centralspindlin complexes, localized by the action of their kinesin-like protein component, position and activate a cortical equatorial ring of Rho GTPase exchange factors. The resulting ring of activated Rho would then trigger a cascade of events leading to formation and constriction of the contractile ring.
mesh_terms: D000205:Actomyosin / Q000378:metabolism*; D000818:Animals; D002455:Cell Division; D003285:Contractile Proteins / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism*
chemical_list: D003285:Contractile Proteins; D029721:Drosophila Proteins; D000205:Actomyosin