The thrombin receptor, PAR-1, causes transformation by activation of Rho-mediated signaling pathways

Oncogene. 2001 Apr 12;20(16):1953-63. doi: 10.1038/sj.onc.1204281.


We utilized a cDNA expression library derived from the B6SutA(1) mouse myeloid progenitor cell line to search for novel oncogenes that promote growth transformation of NIH3T3 cells. A 2.2 kb transforming cDNA was recovered that encodes the wild type thrombin-stimulated G protein-coupled receptor PAR-1. In addition to its potent focus forming activity, constitutive overexpression of PAR-1 in NIH3T3 cells promoted the loss of anchorage- and serum-dependent growth. Although inhibitors of thrombin failed to block PAR-1 transforming activity, a PAR-1 mutant that cannot be cleaved by thrombin was nontransforming. Since the foci of transformed cells induced by PAR-1 bear a striking resemblance to those induced by activated RhoA, we determined if PAR-1 transformation was due to the aberrant activation of a specific Rho family member. Like RhoA, PAR-1 cooperated with activated Raf-1 and caused synergistic enhancement of transforming activity, induced stress fibers when microinjected into porcine aortic endothelial cells, stimulated the activity of the serum response factor and NF-kappaB transcription factors, and PAR-1 transformation was blocked by co-expression of dominant negative RhoA. Finally, PAR-1 transforming activity was blocked by pertussis toxin and by co-expression of the RGS domain of Lsc, implicating Galpha(i) and Galpha(12)/Galpha(13) subunits, respectively, as mediators of PAR-1 transformation. Taken together, these observations suggest that PAR-1 growth transformation is mediated, in part, by activation of RhoA.

Publication types

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

MeSH terms

  • 3T3 Cells / cytology
  • 3T3 Cells / metabolism
  • 3T3 Cells / physiology
  • Actins / metabolism
  • Animals
  • Cell Adhesion / physiology
  • Cell Division / physiology
  • Cell Line
  • Cell Transformation, Neoplastic* / genetics
  • Cell Transformation, Neoplastic* / metabolism
  • DNA, Complementary / genetics
  • DNA-Binding Proteins / physiology
  • GTP-Binding Protein alpha Subunits, G12-G13
  • Heterotrimeric GTP-Binding Proteins / physiology
  • Mice
  • Myeloid Cells / physiology
  • Receptor, PAR-1
  • Receptors, Thrombin / biosynthesis
  • Receptors, Thrombin / genetics
  • Receptors, Thrombin / physiology*
  • Signal Transduction / physiology*
  • Transfection
  • rho GTP-Binding Proteins / metabolism
  • rhoA GTP-Binding Protein / physiology*


  • Actins
  • DNA, Complementary
  • DNA-Binding Proteins
  • Receptor, PAR-1
  • Receptors, Thrombin
  • GTP-Binding Protein alpha Subunits, G12-G13
  • Heterotrimeric GTP-Binding Proteins
  • rho GTP-Binding Proteins
  • rhoA GTP-Binding Protein