The Ras target AF-6 is a substrate of the fam deubiquitinating enzyme

Shinichiro Taya, Takaharu Yamamoto, Kyoko Kano, Yoji Kawano, Akihiro Iwamatsu, Tomoko Tsuchiya, Keiji Tanaka, Masami Kanai-Azuma, Stephen A. Wood, John S. Mattick, Kozo Kaibuchi

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104 Citations (Scopus)


The Ras target AF-6 has been shown to serve as one of the peripheral components of cell-cell adhesions, and is thought to participate in cell- cell adhesion regulation downstream of Ras. We here purified an AF-6- interacting protein with a molecular mass of ~220 kD (p220) to investigate the function of AF-6 at cell-cell adhesions. The peptide sequences of p220 were identical to the amino acid sequences of mouse Fam. Fam is homologous to a deubiquitinating enzyme in Drosophila, the product of the fat facets gene. Recent genetic analyses indicate that the deubiquitinating activity of the fat facets product plays a critical role in controlling the cell fate. We found that Fam accumulated at the cell-cell contact sites of MDCKII cells, but not at free ends of plasma membranes. Fam was partially colocalized with AF-6 and interacted with AF-6 in vivo and in vitro. We also showed that AF-6 was ubiquitinated in intact cells, and that Fam prevented the ubiquitination of AF-6. These results indicate that AF-6 forms a complex with and serves as one of the substrates for Fam, and suggest that the degradation of peripheral components of cell-cell adhesions may be regulated by Fam.

Original languageEnglish
Pages (from-to)1053-1062
Number of pages10
JournalJournal of Cell Biology
Issue number4
Publication statusPublished - Aug 24 1998
Externally publishedYes


  • AF-6
  • Cell-cell adhesions
  • Deubiquitinating enzyme
  • Fam
  • Ubiquitination

ASJC Scopus subject areas

  • Cell Biology


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