Coordination of microtubules and the actin cytoskeleton by the Rho effector mDia1

Nat Cell Biol. 2001 Jan;3(1):8-14. doi: 10.1038/35050598.


Coordination of microtubules and the actin cytoskeleton is important in several types of cell movement. mDia1 is a member of the formin-homology family of proteins and an effector of the small GTPase Rho. It contains the Rho-binding domain in its amino terminus and two distinct regions of formin homology, FH1 in the middle and FH2 in the carboxy terminus. Here we show that expression of mDia1(DeltaN3), an active mDia1 mutant containing the FH1 and FH2 regions without the Rho-binding domain, induces bipolar elongation of HeLa cells and aligns microtubules in parallel to F-actin bundles along the long axis of the cell. The cell elongation and microtubule alignment caused by this mutant is abolished by co-expression of an FH2-region fragment, and expression of mDia1(DeltaN3) containing point mutations in the FH2 region causes an increase in the amount of disorganized F-actin without cell elongation and microtubule alignment. These results indicate that mDia1 may coordinate microtubules and F-actin through its FH2 and FH1 regions, respectively.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actins / drug effects
  • Actins / metabolism*
  • Actins / ultrastructure
  • Brefeldin A / pharmacology
  • Carrier Proteins / drug effects
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Adhesion / drug effects
  • Cell Adhesion / genetics
  • Cell Movement / drug effects
  • Cell Movement / physiology*
  • Cell Size / drug effects
  • Cell Size / genetics
  • Cytochalasin D / pharmacology
  • Cytoskeleton / drug effects
  • Cytoskeleton / metabolism*
  • Cytoskeleton / ultrastructure
  • Golgi Apparatus / drug effects
  • Golgi Apparatus / metabolism
  • HeLa Cells
  • Humans
  • Microtubules / drug effects
  • Microtubules / metabolism*
  • Microtubules / ultrastructure
  • Molecular Sequence Data
  • Nocodazole / pharmacology
  • Phenotype
  • Protein Structure, Tertiary / drug effects
  • Protein Structure, Tertiary / genetics*
  • Sequence Homology, Amino Acid
  • Tubulin / drug effects
  • Tubulin / metabolism
  • rho GTP-Binding Proteins / drug effects
  • rho GTP-Binding Proteins / genetics
  • rho GTP-Binding Proteins / metabolism*


  • Actins
  • Carrier Proteins
  • Tubulin
  • Brefeldin A
  • Cytochalasin D
  • rho GTP-Binding Proteins
  • Nocodazole