Identification of the first Rho-GEF inhibitor, TRIPalpha, which targets the RhoA-specific GEF domain of Trio

FEBS Lett. 2002 Jul 17;523(1-3):35-42. doi: 10.1016/s0014-5793(02)02928-9.


The Rho-guanine nucleotide exchange factors (Rho-GEFs) remodel the actin cytoskeleton via their Rho-GTPase targets and affect numerous physiological processes such as transformation and cell motility. They are therefore attractive targets to design specific inhibitors that may have therapeutic applications. Trio contains two Rho-GEF domains, GEFD1 and GEFD2, which activate the Rac and RhoA pathways, respectively. Here we have used a genetic screen in yeast to select in vivo peptides coupled to thioredoxin, called aptamers, that could inhibit GEFD2 activity. One aptamer, TRIAPalpha (TRio Inhibitory APtamer), specifically blocks GEFD2-exchange activity on RhoA in vitro. The corresponding peptide sequence, TRIPalpha, inhibits TrioGEFD2-mediated activation of RhoA in intact cells and specifically reverts the neurite retraction phenotype induced by TrioGEFD2 in PC12 cells. Thus TRIPalpha is the first Rho-GEF inhibitor isolated so far, and represents an important step in the design of inhibitors for the expanding family of Rho-GEFs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Aptamers, Peptide
  • COS Cells / metabolism
  • Chlorocebus aethiops
  • Guanine Nucleotide Exchange Factors / antagonists & inhibitors*
  • Guanine Nucleotide Exchange Factors / metabolism
  • Guanine Nucleotide Exchange Factors / pharmacology*
  • Molecular Sequence Data
  • PC12 Cells / metabolism
  • Peptides / metabolism
  • Peptides / pharmacology
  • Phosphoproteins / antagonists & inhibitors*
  • Phosphoproteins / metabolism
  • Protein Structure, Tertiary
  • Protein-Serine-Threonine Kinases / antagonists & inhibitors*
  • Protein-Serine-Threonine Kinases / metabolism
  • Rats
  • Saccharomyces cerevisiae Proteins*
  • Thioredoxins / metabolism
  • rac GTP-Binding Proteins / metabolism
  • rhoA GTP-Binding Protein / metabolism*


  • Aptamers, Peptide
  • Guanine Nucleotide Exchange Factors
  • Peptides
  • Phosphoproteins
  • Saccharomyces cerevisiae Proteins
  • TRIPalpha protein, S cerevisiae
  • Thioredoxins
  • Protein-Serine-Threonine Kinases
  • rac GTP-Binding Proteins
  • rhoA GTP-Binding Protein