H/ACA ribonucleoprotein particles (RNPs) are a family of RNA pseudouridine synthases that specify modification sites through guide RNAs. The function of these H/ACA RNPs is essential for biogenesis of the ribosome, splicing of precursor mRNAs (pre-mRNAs), maintenance of telomeres and probably for additional cellular processes []. All H/ACA RNPs contain a specific RNA component (snoRNA or scaRNA) and at least four proteins common to all such particles: Cbf5, Gar1, Nhp2 and Nop10. These proteins are highly conserved from yeast to mammals and homologues are also present in archaea []. The H/ACA protein complex contains a stable core composed of Cbf5 and Nop10, to which Gar1 and Nhp2 subsequently bind [].In eukaryotes Nop10 is a nucleolar protein that is specifically associated with H/ACA snoRNAs. It is essential for normal 18S rRNA production and rRNA pseudouridylation by the ribonucleoprotein particles containing H/ACA snoRNAs (H/ACA snoRNPs). Nop10 is probably necessary for the stability of these RNPs [].
Nop10 is a component of the small nucleolar ribonucleoprotein particles containing H/ACA-type snoRNAs (H/ACA snoRNPs). H/ACA snoRNPs are primarily responsible for catalysing the isomerisation of uridine to pseudouridine (Psi) in ribosomal and other cellular RNAs. The protein component of the H/ACA snoRNP consists of Cbf5, Gar1, Nhp2 and Nop10. The complex contains a stable core composed of Cbf5 and Nop10, to which Gar1 and Nhp2 subsequently bind. Nop10 has an essential role in the assembly and activity of these particles and binds directly to the Cbf5 to form the minimal active enzyme in archaea. The complex interacts with snoRNAs, Nop10 acting as a molecular adaptor for guiding snoRNP assembly [].
H/ACA ribonucleoprotein particles (RNPs) are a family of RNA pseudouridine synthases that specify modification sites through guide RNAs. The function of these H/ACA RNPs is essential for biogenesis of the ribosome, splicing of precursor mRNAs (pre-mRNAs), maintenance of telomeres and probably for additional cellular processes []. All H/ACA RNPs contain a specific RNA component (snoRNA or scaRNA) and at least four proteins common to all such particles: Cbf5, Gar1, Nhp2 and Nop10. These proteins are highly conserved from yeast to mammals and homologues are also present in archaea []. The H/ACA protein complex contains a stable core composed of Cbf5 and Nop10, to which Gar1 and Nhp2 subsequently bind [].In eukaryotes Nop10 is a nucleolar protein that is specifically associated with H/ACA snoRNAs. It is essential for normal 18S rRNA production and rRNA pseudouridylation by the ribonucleoprotein particles containing H/ACA snoRNAs (H/ACA snoRNPs). Nop10 is probably necessary for the stability of these RNPs []. The Nop10 domain structure has a rubredoxin-like fold.
