A Novel Human Nucleolar Protein, Nop132, Binds to the G Proteins, RRAG A/C/D

Takeshi Sekiguchi, Yuko Todaka, Yonggang Wang, Eiji Hirose, Nobutaka Nakashima, Takeharu Nishimoto

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Abstract

RRAG A (Rag A)/Gtr1p is a member of the Ras-like small G protein family that genetically interacts with RCC1, a guanine nucleotide exchange factor for RanGTPase. RRAG A/Gtr1p forms a heterodimer with other G proteins, RRAG C and RRAG D/Gtr2p, in a nucleotide-independent manner. To further elucidate the function of RRAG A/Gtr1p, we isolated a protein that interacts with RRAG A. This protein is a novel nucleolar protein, Nop132. Nop132 is associated with the GTP form, but not the GDP form, of RRAG A, suggesting that RRAG A might regulate Nop132 function. Nop132 is also associated with RRAG C and RRAG D. The Nop132 amino acid sequence is similar to the Saccharomyces cerevisiae nucleolar Nop8p, which is associated with Gtr1p, Gtr2p, and Nip7p. Nop132 also interacts with human Nip7 and is colocalized with RRAG A, RRAG C, and Nip7. RNA interference knockdown of Nop132 inhibited cell growth of HeLa cells.

Original languageEnglish
Pages (from-to)8343-8350
Number of pages8
JournalJournal of Biological Chemistry
Volume279
Issue number9
DOIs
Publication statusPublished - Feb 27 2004

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All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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