A novel human nucleolar protein, Nop132, binds to the G proteins, RRAG A/C/D.
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Sekiguchi T, Todaka Y, Wang Y, Hirose E, Nakashima N, Nishimoto T
A novel human nucleolar protein, Nop132, binds to the G proteins, RRAG A/C/D.
J Biol Chem. 2004 Feb 27;279(9):8343-50. Epub 2003 Dec 4.
- PubMed ID
- 14660641 [ View in PubMed]
- 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.