Anillin-dependent organization of septin filaments promotes intercellular bridge elongation and Chmp4B targeting to the abscission site.
The final step of cytokinesis is abscission when the intercellular bridge (ICB) linking the two new daughter cells is broken. Correct construction of the ICB is crucial for the assembly of factors involved in abscission, a failure in which results in aneuploidy. Using live imaging and subdiffraction microscopy, we identify new anillin-septin cytoskeleton-dependent stages in ICB formation and maturation. We show that after the formation of an initial ICB, septin filaments drive ICB elongation during which tubules containing anillin-septin rings are extruded from the ICB. Septins then generate sites of further constriction within the mature ICB from which they are subsequently removed. The action of the anillin-septin complex during ICB maturation also primes the ICB for the future assembly of the ESCRT III component Chmp4B at the abscission site. These studies suggest that the sequential action of distinct contractile machineries coordinates the formation of the abscission site and the successful completion of cytokinesis.
Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8.
Matthew J
MJ
Renshaw
Jinghe
J
Liu
Brigitte D
BD
Lavoie
Andrew
A
Wilde
D020090:Chromosome Segregation; D003285:Contractile Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D048749:Cytokinesis; D056827:Endosomal Sorting Complexes Required for Transport / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D058112:Septins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
C478397:CHMP4B protein, human; D003285:Contractile Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D034741:RNA, Small Interfering; C095886:anillin; D058112:Septins
cell division; cytokinesis; high-resolution microscopy; mitosis