| Structural highlights
Function
[SHQ1_YEAST] Involved in the early biogenesis steps of box H/ACA snoRNP assembly.[1] [CBF5_YEAST] Plays a central role in ribosomal RNA processing. Probable catalytic subunit of H/ACA small nucleolar ribonucleoprotein (H/ACA snoRNP) complex, which catalyzes pseudouridylation of rRNA. This involves the isomerization of uridine such that the ribose is subsequently attached to C5, instead of the normal N1. Pseudouridine ('psi') residues may serve to stabilize the conformation of rRNAs. May function as a pseudouridine synthase. Binds in vitro to centromeres and microtubules. It is a centromeric DNA-CBF3-binding factor which is involved in mitotic chromosome segregation. Essential for cell growth.[2] [3] [4] [5] [6]
Publication Abstract from PubMed
SHQ1 is an essential assembly factor for H/ACA ribonucleoproteins (RNPs) required for ribosome biogenesis, pre-mRNA splicing, and telomere maintenance. SHQ1 binds dyskerin/NAP57, the catalytic subunit of human H/ACA RNPs, and this interaction is modulated by mutations causing X-linked dyskeratosis congenita. We report the crystal structure of the C-terminal domain of yeast SHQ1, Shq1p, and its complex with yeast dyskerin/NAP57, Cbf5p, lacking its catalytic domain. The C-terminal domain of Shq1p interacts with the RNA-binding domain of Cbf5p and, through structural mimicry, uses the RNA-protein-binding sites to achieve a specific protein-protein interface. We propose that Shq1p operates as a Cbf5p chaperone during RNP assembly by acting as an RNA placeholder, thereby preventing Cbf5p from nonspecific RNA binding before association with an H/ACA RNA and the other core RNP proteins.
The H/ACA RNP assembly factor SHQ1 functions as an RNA mimic.,Walbott H, Machado-Pinilla R, Liger D, Blaud M, Rety S, Grozdanov PN, Godin K, van Tilbeurgh H, Varani G, Meier UT, Leulliot N Genes Dev. 2011 Nov 15;25(22):2398-408. PMID:22085966[7]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Yang PK, Rotondo G, Porras T, Legrain P, Chanfreau G. The Shq1p.Naf1p complex is required for box H/ACA small nucleolar ribonucleoprotein particle biogenesis. J Biol Chem. 2002 Nov 22;277(47):45235-42. Epub 2002 Sep 11. PMID:12228251 doi:10.1074/jbc.M207669200
- ↑ Jiang W, Middleton K, Yoon HJ, Fouquet C, Carbon J. An essential yeast protein, CBF5p, binds in vitro to centromeres and microtubules. Mol Cell Biol. 1993 Aug;13(8):4884-93. PMID:8336724
- ↑ Cadwell C, Yoon HJ, Zebarjadian Y, Carbon J. The yeast nucleolar protein Cbf5p is involved in rRNA biosynthesis and interacts genetically with the RNA polymerase I transcription factor RRN3. Mol Cell Biol. 1997 Oct;17(10):6175-83. PMID:9315678
- ↑ Lafontaine DL, Bousquet-Antonelli C, Henry Y, Caizergues-Ferrer M, Tollervey D. The box H + ACA snoRNAs carry Cbf5p, the putative rRNA pseudouridine synthase. Genes Dev. 1998 Feb 15;12(4):527-37. PMID:9472021
- ↑ Watkins NJ, Gottschalk A, Neubauer G, Kastner B, Fabrizio P, Mann M, Luhrmann R. Cbf5p, a potential pseudouridine synthase, and Nhp2p, a putative RNA-binding protein, are present together with Gar1p in all H BOX/ACA-motif snoRNPs and constitute a common bipartite structure. RNA. 1998 Dec;4(12):1549-68. PMID:9848653
- ↑ Zebarjadian Y, King T, Fournier MJ, Clarke L, Carbon J. Point mutations in yeast CBF5 can abolish in vivo pseudouridylation of rRNA. Mol Cell Biol. 1999 Nov;19(11):7461-72. PMID:10523634
- ↑ Walbott H, Machado-Pinilla R, Liger D, Blaud M, Rety S, Grozdanov PN, Godin K, van Tilbeurgh H, Varani G, Meier UT, Leulliot N. The H/ACA RNP assembly factor SHQ1 functions as an RNA mimic. Genes Dev. 2011 Nov 15;25(22):2398-408. PMID:22085966 doi:10.1101/gad.176834.111
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