Crystal structure of the formin mDIA1 in autoinhibited conformation

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

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Background: Formin proteins utilize a conserved formin homology 2 (FH2) domain to nucleate new actin filaments. In mammalian diaphanous-related formins (DRFs) the FH2 domain is inhibited through an unknown mechanism by intramolecular binding of the diaphanous autoinhibitory domain (DAD) and the diaphanous inhibitory domain (DID). Methodology/Principal Findings: Here we report the crystal structure of a complex between DID and FH2-DAD fragments of the mammalian DRF, mDia1 (mammalian diaphanous 1 also called Drf1 or p140mDia). The structure shows a tetrameric configuration (4 FH2 + 4 DID) in which the actin-binding sites on the FH2 domain are sterically occluded. However biochemical data suggest the full-length mDia1 is a dimer in solution (2 FH2 + 2 DID). Based on the crystal structure, we have generated possible dimer models and found that architectures of all of these models are incompatible with binding to actin filament but not to actin monomer. Furthermore, we show that the minimal functional monomeric unit in the FH2 domain, termed the bridge element, can be inhibited by isolated monomeric DID. NMR data on the bridge-DID system revealed that at least one of the two actin-binding sites on the bridge element is accessible to actin monomer in the inhibited state. Conclusions/Significance: Our findings suggest that autoinhibition in the native DRF dimer involves steric hindrance with the actin filament. Although the structure of a full-length DRF would be required for clarification of the presented models, our work here provides the first structural insights into the mechanism of the DRF autoinhibition.

Original languageEnglish (US)
Article numbere12896
Pages (from-to)1-13
Number of pages13
JournalPLoS One
Volume5
Issue number9
DOIs
StatePublished - 2010

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crystal structure
actin
Conformations
Actins
Crystal structure
microfilaments
Actin Cytoskeleton
binding sites
Dimers
Binding Sites
Monomers
Nuclear magnetic resonance
Proteins
proteins
methodology

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Crystal structure of the formin mDIA1 in autoinhibited conformation. / Otomo, Takanori; Tomchick, Diana R.; Otomo, Chinatsu; Machius, Mischa; Rosen, Michael K.

In: PLoS One, Vol. 5, No. 9, e12896, 2010, p. 1-13.

Research output: Contribution to journalArticle

Otomo, Takanori ; Tomchick, Diana R. ; Otomo, Chinatsu ; Machius, Mischa ; Rosen, Michael K. / Crystal structure of the formin mDIA1 in autoinhibited conformation. In: PLoS One. 2010 ; Vol. 5, No. 9. pp. 1-13.
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