Functional interaction between Rho effector proteins

• Project/Area Number: 18590262
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: General medical chemistry
• Research Institution: Kyoto University
• Principal Investigator: ISHIZAKI Toshimasa Kyoto University, Faculty of medicine, Pharmacology, Research associate (70293876)
• Project Period (FY): 2006 – 2007
• Project Status: Completed (Fiscal Year 2007)
• Budget Amount: ¥3,900,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥300,000); Fiscal Year 2007: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2006: ¥2,600,000 (Direct Cost: ¥2,600,000)
• Keywords: Rho / actin cytoskeleton / mDia / ROCK / cytokinesis / cell migration / vasculogenesis / 細胞接着 / 胚発生

Research Abstract

Directed cell migration requires cell polarization and adhesion turnover, in which the actin cytoskeleton and microtubules work critically. The Rho GTPases induce specific types of actin cytoskeleton and regulate microtubule dynamics. In migrating cells, Cdc42 regulates cell polarity and Rac works in membrane protrusion. However, the role of Rho in migration is little known. Rho acts on two major effectors, ROCK and mDia1, among which mDia1 produces straight actin filaments and aligns microtubules. We found that the Rho-mDia1 pathway regulates polarization and adhesion turnover by aligning microtubules and actin filaments and delivering Apc/Cdc42 and c-Src to their respective sites of action in rat C6 glioma cells.
mDia proteins belong to the formin family proteins that catalyze actin nucleation and polymerization. Although formin family proteins of nonmammalian species such as Drosophila diaphanous are essential in cytokinesis, whether and how mDia proteins function in cytokinesis rema in unknown. To address this issue, we depleted each of the three mDia isoforms in NIH 3T3 cells by RNA interference. Depletion of mDia2 selectively increased the number of binucleate cells. mDia2 accumulates in the cleavage furrow during anaphase to telophase, and concentrates in the midbody at the end of cytokinesis. Depletion of mDia2 induced contraction at aberrant sites of dividing cells, where contractile ring components such as RhoA, myosin, anillin, and phosphorylated ERM accumulated. Treatment with blebbistatin suppressed abnormal contraction, corrected localization of the above components, and revealed that the amount of F-actin at the equatorial region during anaphase/telophase was significantly decreased with mDia2 RNAi. These results demonstrate that mDia2 is essential in mammalian cell cytokinesis and that mDia2-induced F-actin forms a scaffold for the contractile ring and maintains its position in the middle of a dividing cell.
Furthermore, we are also analyzing the role of another Rho effector molecule, ROCK, in vasculogenesis during embryonic development.

Research Products

• [Journal Article] mDia2 Induces the Actin Scaffold for the Contractile Ring and Stabilizes its Position during Cytokinesis in NIH 3T3 Cells. (2008)
  • Author(s): Watanabe S., et. al.
  • Journal Title: Mol Biol Cell. 19 Pages: 2328-2338
  • Description: 「研究成果報告書概要(和文)」より
  • Peer Reviewed
• [Journal Article] mDia2 Induces the Actin Scaffold for the Contractile Ring and Stabilizes Its Position during Cytokinesis in NIH 3T3 Cells (2008)
  • Author(s): Watanabe, S., Ando, Y., Yasuda, S., Hosoya, H., Watanabe, N., Ishizaki, T., Narumiya, S
  • Journal Title: Mol. Cell Biol 19 Pages: 2328-2338
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] The Rho-mDial pathway regulates cell polarity and focal adhesion turnover in migrating cells through mobilizing Apc and c-Src. (2006)
  • Author(s): Yamana N, et. al.
  • Journal Title: Mol. Cell Biol. 26 Pages: 6844-6858
  • Description: 「研究成果報告書概要(和文)」より
  • Peer Reviewed
• [Journal Article] GAP1 family members constitute bifunctional Ras and Rap GTPase-activating proteins. (2006)
  • Author(s): Kupzig S, et. al.
  • Journal Title: J Biol Chem 281 Pages: 9891-9900
  • Description: 「研究成果報告書概要(和文)」より
  • Peer Reviewed
• [Journal Article] The Rho-mDial pathway regulates cell polarity and focal adhesion turnover in migrating cells through mobilizing Apc and c-Src (2006)
  • Author(s): Yamana, N., Arakawa, Y., Nishino, T., Kurokawa, K., Tanji, M., Itoh, RE., Monypenny, J., Ishizaki, T., Bito, H., Nozaki, K., Hashimoto, N., Matsuda, M., Narumiya, S
  • Journal Title: Mol Cell Biol 26 Pages: 6844-6858
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] GAP1 family members constitute bifunctional Ras and Rap GTPase-activating proteins (2006)
  • Author(s): Kupzig, S., Deaconescu, D., Bouyoucef, D., Walker, SA., Liu, Q., Polte, CL., Daumke, O., Ishizaki, T., Lockyer, PJ., Wittinghofer, A., Cullen, PJ
  • Journal Title: J Biol Chem 281 Pages: 9891-9900
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] The Rho-mDial pathway regulates cell polarity and focal adhesion turnover in migrating cells through mobilizing Apc and c-Src. (2006)
  • Author(s): Yamana N et al.
  • Journal Title: Mol. Cell Biol. 26 Pages: 6844-6858
• [Journal Article] GAPl family members constitute bifunctional Ras and Rap GTPase-activating proteins. (2006)
  • Author(s): Kupzig S et al.
  • Journal Title: J Biol Chem. 281 Pages: 9891-9900
• [Journal Article] mDia2 Induces the Actin Scaffold for the Contractile Ring and Stabilizes its Position during Cytokinesis in NIH 3T3 Cells.
  • Author(s): Watanabe S, et. al.
  • Journal Title: Mol Biol Cell (In press)
  • Peer Reviewed