RASSF1A directly antagonizes RhoA activity through the assembly of a Smurf1-mediated destruction complex to suppress tumorigenesis

Min Goo Lee, Seong In Jeong, Kyung Phil Ko, Soon Ki Park, Byung Kyu Ryu, Ick Young Kim, Jeong Kook Kim, Sung Gil Chi

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)


RASSF1A is a tumor suppressor implicated inmany tumorigenic processes;however, the basis for its tumor suppressor functions are not fully understood. Here we show that RASSF1A is a novel antagonist of protumorigenic RhoA activity. Direct interaction between the C-terminal amino acids (256-277) of RASSF1A and active GTP-RhoA was critical for this antagonism. In addition, interaction between the N-terminal amino acids (69-82) of RASSF1A and the ubiquitin E3 ligase Smad ubiquitination regulatory factor 1 (Smurf1) disrupted GTPase activity by facilitating Smurf1-mediated ubiquitination of GTP-RhoA. We noted that the RhoA-binding domain of RASSF1A displayed high sequence homology with Rho-binding motifs in other RhoA effectors, such as Rhotekin. As predicted on this basis, RASSF1A competed with Rhotekin to bind RhoA and to block its activation. RASSF1A mutants unable to bind RhoA or Smurf1 failed to suppress RhoA-induced tumor cell proliferation, drug resistance, epithelial-mesenchymal transition, migration, invasion, and metastasis. Clinically, expression levels of RASSF1A and RhoA were inversely correlated in many types of primary and metastatic tumors and tumor cell lines. Collectively, our findings showed how RASSF1A may suppress tumorigenesis by intrinsically inhibiting the tumorpromoting activity of RhoA, thereby illuminating the potential mechanistic consequences of RASSF1A inactivation in many cancers.

Original languageEnglish
Pages (from-to)1847-1859
Number of pages13
JournalCancer Research
Issue number7
Publication statusPublished - 2016 Apr 1

Bibliographical note

Funding Information:
This work was supported by the Korean Health Technology R&D Project (HI12C1277) and National Research Foundation of Korea (NRF- 2015R1A2A1A01005389).

Publisher Copyright:
© 2016 American Association for Cancer Research.

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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