Opposing actions of septins and Sticky on Anillin promote the transition from contractile to midbody ring.
During cytokinesis, closure of the actomyosin contractile ring (CR) is coupled to the formation of a midbody ring (MR), through poorly understood mechanisms. Using time-lapse microscopy of Drosophila melanogaster S2 cells, we show that the transition from the CR to the MR proceeds via a previously uncharacterized maturation process that requires opposing mechanisms of removal and retention of the scaffold protein Anillin. The septin cytoskeleton acts on the C terminus of Anillin to locally trim away excess membrane from the late CR/nascent MR via internalization, extrusion, and shedding, whereas the citron kinase Sticky acts on the N terminus of Anillin to retain it at the mature MR. Simultaneous depletion of septins and Sticky not only disrupted MR formation but also caused earlier CR oscillations, uncovering redundant mechanisms of CR stability that can partly explain the essential role of Anillin in this process. Our findings highlight the relatedness of the CR and MR and suggest that membrane removal is coordinated with CR disassembly.
Centre de Cancérologie Charles Bruneau, Centre Hospitalier Universitaire Sainte-Justine Centre de Recherche, Montréal, Québec H3T 1C5, Canada.
Nour
N
El Amine
Amel
A
Kechad
Silvana
S
Jananji
Gilles R X
GR
Hickson
D000205:Actomyosin; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003285:Contractile Proteins / Q000378:metabolism*; D048749:Cytokinesis; D003599:Cytoskeleton / Q000378:metabolism; D004331:Drosophila melanogaster; D056827:Endosomal Sorting Complexes Required for Transport / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering; D058112:Septins / Q000235:genetics / Q000378:metabolism*
D003285:Contractile Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D047908:Intracellular Signaling Peptides and Proteins; D034741:RNA, Small Interfering; C095886:anillin; D000205:Actomyosin; C115635:citron-kinase; D017346:Protein Serine-Threonine Kinases; D058112:Septins