H/ACA ribonucleoprotein complex, subunit Gar1, archaea (IPR020321)

Short name: H/ACA_rnp_Gar1_arc

Overlapping homologous superfamilies

Family relationships


H/ACA ribonucleoprotein particles (RNPs) are a family of RNA pseudouridine synthases that specify modification sites through guide RNAs. More than 100 mammalian H/ACA RNAs form an equal number of ribonucleoproteins (RNPs) by associating with the same four core proteins: Cbf5 (the Psi-synthase), Gar1, Nhp2 (L7Ae in archaea) and Nop10. 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 [PMID: 16647858].

Crystal structures of archaeal H/ACA protein complexes show how the same four proteins accommodate more than 100 distinct but related H/ACA RNAs [PMID: 16943774]. The complex contains a stable core composed of Cbf5 and Nop10, to which Gar1 and Nhp2 subsequently bind. The smallest of these proteins, Nop10, has an essential role in the assembly and activity of these particles and binds directly to the Psi-synthase to form the minimal active enzyme in archaea. The complex interacts with snoRNAs, Nop10 acting as a molecular adaptor for guiding snoRNP assembly [PMID: 18473479].

Archaeal Gar1 have been shown to increase the catalytic activity of Cbf5 in pseudouridylating tRNA [PMID: 22993689].

GO terms

Biological Process

GO:0001522 pseudouridine synthesis
GO:0042254 ribosome biogenesis

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.