Anillin and the septins promote asymmetric ingression of the cytokinetic furrow.
During cytokinesis, constriction of a cortical contractile ring generates a furrow that partitions one cell into two. The contractile ring contains three filament systems: actin, bipolar myosin II filaments, and septins, GTP-binding hetero-oligomers that polymerize to form a membrane-associated lattice. The contractile ring also contains a potential filament crosslinker, Anillin, that binds all three filament types. Here, we show that the contractile ring possesses an intrinsic symmetry-breaking mechanism that promotes asymmetric furrowing. Asymmetric ingression requires Anillin and the septins, which promote the coalescence of components on one side of the contractile ring, but is insensitive to a 10-fold reduction in myosin II levels. When asymmetry is disrupted, cytokinesis becomes sensitive to partial inhibition of contractility. Thus, asymmetric furrow ingression, a prevalent but previously unexplored feature of cell division in metazoans, is generated by the action of two conserved furrow components and serves a mechanical function that makes cytokinesis robust.
Maddox
Amy Shaub
AS
Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine (UCSD), CMM-East Rm. 3053, 9500 Gilman Drive, La Jolla, CA 92093, USA. amaddox@ucsd.edu
Lewellyn
Lindsay
L
Desai
Arshad
A
Oegema
Karen
K
D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D003285:Contractile Proteins / Q000378:metabolism*; D048749:Cytokinesis; D004331:Drosophila melanogaster; D004625:Embryo, Nonmammalian / Q000166:cytology; D024462:Myosin Type II / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D003285:Contractile Proteins; D011993:Recombinant Fusion Proteins; C095886:anillin; D024462:Myosin Type II