Structural basis of Rho GTPase-mediated activation of the formin mDia1

Takanori Otomo, Chinatsu Otomo, Diana R. Tomchick, Mischa Machius, Michael K. Rosen

Research output: Contribution to journalArticlepeer-review

200 Scopus citations


Diaphanous-related formins (DRFs) regulate dynamics of unbranched actin filaments during cell contraction and cytokinesis. DRFs are autoinhibited through intramolecular binding of a Diaphanous autoinhibitory domain (DAD) to a conserved N-terminal regulatory element. Autoinhibition is relieved through binding of the GTPase RhoA to the N-terminal element. We report the crystal structure of the dimeric regulatory domain of the DRF, mDia1. Dimerization is mediated by an intertwined six-helix bundle, from which extend two Diaphanous inhibitory domains (DIDs) composed of five armadillo repeats. NMR and biochemical mapping indicate the RhoA and DAD binding sites on the DID partially overlap, explaining activation of mDia1 by the GTPase. RhoA binding also requires an additional structurally independent segment adjacent to the DID. This regulatory construction, involving a GTPase binding site spanning a flexibly tethered arm and the inhibitory module, is observed in many autoinhibited effectors of Ras superfamily GTPases, suggesting evolutionary pressure for this design.

Original languageEnglish (US)
Pages (from-to)273-281
Number of pages9
JournalMolecular cell
Issue number3
StatePublished - Apr 29 2005

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


Dive into the research topics of 'Structural basis of Rho GTPase-mediated activation of the formin mDia1'. Together they form a unique fingerprint.

Cite this