Dissecting the role of Rho-mediated signaling in contractile ring formation

Keiju Kamijo, Naoya Ohara, Mitsuhiro Abe, Takashi Uchimura, Hiroshi Hosoya, Jae Seon Lee, Toru Miki

Research output: Contribution to journalArticlepeer-review

68 Citations (Scopus)


In anaphase, microtubules provide a specification signal for positioning of the contractile ring. However, the nature of the signal remains unknown. The small GTPase Rho is a potent regulator of cytokinesis, but the involvement of Rho in contractile ring formation is disputed. Here, we show that Rho serves as a microtubule-dependent signal that specifies the position of the contractile ring. We found that Rho translocates to the equatorial region before furrow ingression. The Rho-specific inhibitor C3 exoenzyme and small interfering RNA to the Rho GDP/GTP exchange factor ECT2 prevent this translocation and disrupt contractile ring formation, indicating that active Rho is required for contractile ring formation. ECT2 forms a complex with the GTPase-activating protein MgcRacGAP and the kinesinlike protein MKLP1 at the central spindle, and the localization of ECT2 at the central spindle depends on MgcRacGAP and MKLP1. In addition, we show that the bundled microtubules direct Rho-mediated signaling molecules to the furrowing site and regulate furrow formation. Our study provides strong evidence for the requirement of Rho-mediated signaling in contractile ring formation.

Original languageEnglish
Pages (from-to)43-55
Number of pages13
JournalMolecular Biology of the Cell
Issue number1
Publication statusPublished - Jan 2006
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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