Rac GTPase Activity is Essential for EGF-induced Mitogenesis

Byung Chul Kim, Ji Young Yi, Sun Ju Yi, In Cheol Shin, Kwon Soo Ha, Byung H. Jhun, Soon Bong Hwang, Jae Hong Kim

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


Rac, a member of the Rho family GTPases, has been implicated in the regulation of a wide range of biological processes including actin remodeling, cell transformation, G1 cell cycle progression, and gene expression. To determine whether Rac GTPase activity is required for epidermal growth factor-induced mitogenesis, Rat-2 stable cells expressing a dominant-negative Rac1 mutant, RacN17, were prepared. Exposure to EGF exhibited a significantly restricted growth response in Rat-2-RacN17 cells compared to Rat-2 parental cells, suggesting an essential role of Rac in EGF-induced mitogenesis. In contrast, addition of Iysophosphatidic acid exerted the same level of growth in Rat-2 and Rat-2-RacN17 cells. To gain further evidence for the essential role of Rac in EGF-induced mitogenesis, we performed the microinjection experiment. EGF-induced DNA synthesis was significantly blocked by microinjection of recombinant RacN17 protein, and not control IgG. Our further study to analyze the downstream mediator of Rac in EGF-signaling to mitogenesis demonstrated that Rac-activated phospholipase A2 plays a critical role. Taken together, our results suggest that the "Rac and Rac-activated PLA2" cascade is one of the major mitogenic pathways induced by EGF.

Original languageEnglish
Pages (from-to)90-95
Number of pages6
JournalMolecules and cells
Issue number1
Publication statusPublished - 1998 Feb 28
Externally publishedYes


  • EGF
  • Mitogenesis
  • Phospholipase A
  • Rac

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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