A novel Cdc42Hs mutant induces cellular transformation

Curr Biol. 1997 Oct 1;7(10):794-7. doi: 10.1016/s0960-9822(06)00338-1.


Cdc42Hs is a small GTPase of the Rho-subfamily, which regulates signaling pathways that influence cell morphology and polarity, cell-cycle progression and transcription. An essential role for Cdc42Hs in cell growth regulation has been suggested by the finding that the Dbl oncoprotein is an upstream activator-a guanine nucleotide exchange factor (GEF)-for Cdc42Hs, and that activated mutants of the closely related GTPases Rac and Rho are transforming. As we were unable to obtain significant over-expression of GTPase-defective Cdc42Hs mutants, we have generated a mutant, Cdc42Hs(F28L), which can undergo spontaneous GTP-GDP exchange while maintaining full GTPase activity, and thus should exhibit functional activities normally imparted by Dbl. In cultured fibroblasts, Cdc42Hs(F28L) activated the c-Jun kinase (JNK1) and stimulated filopodia formation. Cells stably expressing Cdc42Hs(F28L) also exhibited several hallmarks of transformation-reduced contact inhibition, lower dependence on serum for growth, and anchorage-independent growth. Our findings indicate that Cdc42Hs plays a role in cell proliferation, and is a likely physiological mediator of Dbl-induced transformation.

Publication types

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

MeSH terms

  • 3T3 Cells
  • Animals
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Division
  • Cell Transformation, Neoplastic*
  • Enzyme Activation
  • GTP-Binding Proteins / genetics
  • GTP-Binding Proteins / metabolism*
  • Guanosine 5'-O-(3-Thiotriphosphate) / metabolism
  • Guanosine Diphosphate / metabolism
  • JNK Mitogen-Activated Protein Kinases
  • Mice
  • Mitogen-Activated Protein Kinases*
  • Mutation*
  • cdc42 GTP-Binding Protein


  • Cell Cycle Proteins
  • Guanosine Diphosphate
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Calcium-Calmodulin-Dependent Protein Kinases
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinases
  • GTP-Binding Proteins
  • cdc42 GTP-Binding Protein