Mutations in sticky lead to defective organization of the contractile ring during cytokinesis and are enhanced by Rho and suppressed by Rac.
The contractile ring is a highly dynamic structure, but how this dynamism is accomplished remains unclear. Here, we report the identification and analysis of a novel Drosophila gene, sticky (sti), essential for cytokinesis in all fly proliferating tissues. sti encodes the Drosophila orthologue of the mammalian Citron kinase. RNA interference-mediated silencing of sti in cultured cells causes them to become multinucleate. Components of the contractile ring and central spindle are recruited normally in such STICKY-depleted cells that nevertheless display asymmetric furrowing and aberrant blebbing. Together with an unusual distribution of F-actin and Anillin, these phenotypes are consistent with defective organization of the contractile ring. sti shows opposite genetic interactions with Rho and Rac genes suggesting that these GTPases antagonistically regulate STICKY functions. Similar genetic evidence indicates that RacGAP50C inhibits Rac during cytokinesis. We discuss that antagonism between Rho and Rac pathways may control contractile ring dynamics during cytokinesis.
D'Avino
Pier Paolo
PP
Cancer Research UK Cell Cycle Genetics Research Group, Department of Genetics, University of Cambridge, Downing Site, CB2 3EH. p.davino@gen.cam.ac.uk
Savoian
Matthew S
MS
Glover
David M
DM
D000199:Actins / Q000096:biosynthesis; D000483:Alleles; D000818:Animals; D030801:Animals, Genetically Modified; D015153:Blotting, Western; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D002469:Cell Separation; D003001:Cloning, Molecular; D003285:Contractile Proteins / Q000096:biosynthesis; D004330:Drosophila; D005434:Flow Cytometry; D020558:GTP Phosphohydrolases / Q000378:metabolism; D020868:Gene Silencing; D005816:Genetic Complementation Test; D047908:Intracellular Signaling Peptides and Proteins; D008938:Mitosis; D008954:Models, Biological; D008957:Models, Genetic; D009154:Mutation; D010641:Phenotype; D011123:Polyploidy; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000502:physiology; D034622:RNA Interference; D020744:rac GTP-Binding Proteins / Q000378:metabolism*; D020741:rho GTP-Binding Proteins / Q000378:metabolism*
D000199:Actins; D003285:Contractile Proteins; D047908:Intracellular Signaling Peptides and Proteins; C095886:anillin; C115635:citron-kinase; D017346:Protein Serine-Threonine Kinases; D020558:GTP Phosphohydrolases; D020744:rac GTP-Binding Proteins; D020741:rho GTP-Binding Proteins