The H/ACA RNP assembly factor SHQ1 functions as an RNA mimic.

Abstract

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.

• Authors: Hélène Walbott, Rosario Machado-Pinilla, Dominique Liger, Magali Blaud, Stéphane Réty, Petar N Grozdanov, Kate Godin, Herman van Tilbeurgh, Gabriele Varani, U Thomas Meier, Nicolas Leulliot
• Journal: Genes & development (Genes Dev) Vol. 25 Issue 22 Pg. 2398-408 (Nov 15 2011) ISSN: 1549-5477 [Electronic] United States
• PMID: 22085966 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Microtubule-Associated Proteins
• NAP57
• Nuclear Proteins
• RNA, Fungal
• Recombinant Proteins
• Ribonucleoproteins, Small Nuclear
• Ribonucleoproteins, Small Nucleolar
• Saccharomyces cerevisiae Proteins
• Shq1 protein, S cerevisiae
• Hydro-Lyases
• CBF5 protein, S cerevisiae

Topics

• Cell Survival
• Humans
• Hydro-Lyases (chemistry, metabolism)
• Microtubule-Associated Proteins (chemistry, metabolism)
• Models, Molecular
• Molecular Mimicry
• Mutation
• Nuclear Proteins (chemistry, genetics, metabolism)
• Protein Binding
• Protein Folding
• Protein Structure, Tertiary
• RNA, Fungal (metabolism)
• Recombinant Proteins (metabolism)
• Ribonucleoproteins, Small Nuclear (chemistry, metabolism)
• Ribonucleoproteins, Small Nucleolar (chemistry, metabolism)
• Saccharomyces cerevisiae (chemistry, genetics, metabolism)
• Saccharomyces cerevisiae Proteins (chemistry, genetics, metabolism)