Implication of the small GTPase Rac1 in the apoptosis induced by UV in Rat-2 fibroblasts

Young Woo Eom, Min Hyuk Yoo, Chang Hoon Woo, Ki Chul Hwang, Woo Keun Song, Yung Joon Yoo, Jang Soo Chun, Jae Hong Kim

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)


Exposure of mammalian cells to ultraviolet (UV) light elicits a cellular response and also lead to apoptotic cell death. However, the role of Rac, a member of Rho family GTPases, in the UV-induced apoptosis has never been examined. In UV-irradiated Rat-2 fibroblasts, nuclear fragmentation began to be observed within 2 h and the total viability of Rat-2 cells were only about 15% at 6 h following by UV irradiation, whereas the total viability in Rat2-RacN17 cells stably expressing RacN17, a dominant negative Rac1 mutant, was almost close to 67%. Pretreatment with SB203580, a specific inhibitor of p38 kinase, likewise attenuated UV-induced cell death, but PD98059, a MEK inhibitor, did not. Thus, Rac1 and p38 kinase appear to be components in the apoptotic signaling pathway induced by UV irradiation in Rat-2 fibroblasts. In addition, our results show that p38 kinase stimulation by UV is dramatically inhibited by RacN17, suggesting that p38 kinase is situated downstream of Rac1 in the UV signaling to apoptosis.

Original languageEnglish
Pages (from-to)825-829
Number of pages5
JournalBiochemical and biophysical research communications
Issue number3
Publication statusPublished - 2001
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by grants from the National Research Laboratory (NRL), Life Phenomena and Function Research Group Program-2000 from the Ministry of Science and Technology, and the Brain Korea 21 (BK21) program.


  • Apoptosis
  • Rac
  • UV
  • p38 kinase

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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