Transforming mutations of RAC guanosine triphosphatases in human cancers

Masahito Kawazu, Toshihide Ueno, Kenji Kontani, Yoshitaka Ogita, Mizuo Ando, Kazutaka Fukumura, Azusa Yamato, Manabu Soda, Kengo Takeuchi, Yoshio Miki, Hiroyuki Yamaguchi, Takahiko Yasuda, Tomoki Naoe, Yoshihiro Yamashita, Toshiaki Katada, Young Lim Choi, Hiroyuki Mano

Research output: Contribution to journalArticlepeer-review

89 Citations (Scopus)


Members of the RAS superfamily of small guanosine triphosphatases (GTPases) transition between GDP-bound, inactive and GTPbound, active states and thereby function as binary switches in the regulation of various cellular activities. Whereas HRAS, NRAS, and KRAS frequently acquire transforming missense mutations in human cancer, little is known of the oncogenic roles of other small GTPases, including Ras-related C3 botulinum toxin substrate (RAC) proteins. We show that the human sarcoma cell line HT1080 harbors both NRAS(Q61K) and RAC1(N92I) mutant proteins. Whereas both of these mutants were able to transform fibroblasts, knockdown experiments indicated that RAC1(N92I) may be the essential growth driver for this cell line. Screening for RAC1, RAC2, or RAC3 mutations in cell lines and public databases identified several missense mutations for RAC1 and RAC2, with some of the mutant proteins, including RAC1(P29S), RAC1(C157Y), RAC2(P29L), and RAC2(P29Q), being found to be activated and transforming. P29S, N92I, and C157Y mutants of RAC1 were shown to exist preferentially in the GTP-bound state as a result of a rapid transition from the GDP-bound state, rather than as a result of a reduced intrinsic GTPase activity. Activating mutations of RAC GTPases were thus found in a wide variety of human cancers at a low frequency; however, given their marked transforming ability, the mutant proteins are potential targets for the development of new therapeutic agents.

Original languageEnglish
Pages (from-to)3029-3034
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number8
Publication statusPublished - Feb 19 2013
Externally publishedYes


  • Oncogene
  • Resequencing

ASJC Scopus subject areas

  • General


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