Function
Non-catalytic component of the H/ACA small nucleolar ribonucleoprotein (H/ACA snoRNP), which catalyzes pseudouridylation of rRNA and is required for ribosome biogenesis (PubMed:9843512, PubMed:9848653). This involves the isomerization of uridine such that the ribose is subsequently attached to C5, instead of the normal N1 (PubMed:9843512, PubMed:9848653). Pseudouridine (psi) residues may serve to stabilize the conformation of rRNAs (PubMed:9843512, PubMed:9848653). The H/ACA snoRNP complex also mediates pseudouridylation of other types of RNAs (PubMed:21131909). The H/ACA snoRNP complex mediates pseudouridylation at position 93 in U2 snRNA (PubMed:21131909). Essential for growth (PubMed:9843512). Directly binds H/ACA snoRNAs (PubMed:11433018).