A RhoGEF and Rho family GTPase-activating protein complex links the contractile ring to cortical microtubules at the onset of cytokinesis.
The mechanism that positions the cytokinetic contractile ring is unknown, but derives from the spindle midzone. We show that an interaction between the Rho GTP exchange factor, Pebble, and the Rho family GTPase-activating protein, RacGAP50C, connects the contractile ring to cortical microtubules at the site of furrowing in D. melanogaster cells. Pebble regulates actomyosin organization, while RacGAP50C and its binding partner, the Pavarotti kinesin-like protein, regulate microtubule bundling. All three factors are required for cytokinesis. As furrowing begins, these proteins colocalize to a cortical equatorial ring. We propose that RacGAP50C-Pavarotti complexes travel on cortical microtubules to the cell equator, where they associate with the Pebble RhoGEF to position contractile ring formation and coordinate F-actin and microtubule remodeling during cytokinesis.
Somers
W Gregory
WG
Centre for the Molecular Genetics of Development, Research School of Biological Sciences, Australian National University, Canberra, ACT 0200, Australia.
Saint
Robert
R
D000818:Animals; D002455:Cell Division; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology* / Q000196:embryology / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D046911:Macromolecular Substances; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D064067:Rho Guanine Nucleotide Exchange Factors; D008941:Spindle Apparatus; D020798:Two-Hybrid System Techniques; D014921:Wings, Animal / Q000166:cytology / Q000196:embryology / Q000378:metabolism
D029721:Drosophila Proteins; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D046911:Macromolecular Substances; D008869:Microtubule-Associated Proteins; C121865:Pbl protein, Drosophila; D012333:RNA, Messenger; D064067:Rho Guanine Nucleotide Exchange Factors; C490516:pav protein, Drosophila; C085379:rho GTPase-activating protein