Required for ribosome biogenesis and telomere maintenance. Part of the 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. Each rRNA can contain up to 100 pseudouridine ('psi') residues, which may serve to stabilize the conformation of rRNAs. May also be required for correct processing or intranuclear trafficking of TERC, the RNA component of the telomerase reverse transcriptase (TERT) holoenzyme. Part of the H/ACA small nucleolar ribonucleoprotein (H/ACA snoRNP) complex, which contains NHP2/NOLA2, GAR1/NOLA1, NOP10/NOLA3, and DKC1/NOLA4, which is presumed to be the catalytic subunit (PubMed:11074001). The complex contains a stable core formed by binding of one or two NOP10-DKC1 heterodimers to NHP2; GAR1 subsequently binds to this core via DKC1 (PubMed:11074001). The complex binds a box H/ACA small nucleolar RNA (snoRNA), which may target the specific site of modification within the RNA substrate (PubMed:16601202). During assembly, the complex contains NAF1 instead of GAR1/NOLA1 (PubMed:11074001, PubMed:16601202). The complex also interacts with TERC, which contains a 3'-terminal domain related to the box H/ACA snoRNAs (PubMed:11074001, PubMed:16601202). Specific interactions with snoRNAs or TERC are mediated by GAR1 and NHP2 (PubMed:11074001, PubMed:16601202). Associates with NOLC1/NOPP140 (PubMed:11074001, PubMed:16601202). H/ACA snoRNPs interact with the SMN complex, consisting of SMN1 or SMN2, GEMIN2/SIP1, DDX20/GEMIN3, and GEMIN4 (PubMed:11074001, PubMed:16601202). This is mediated by interaction between GAR1 and SMN1 or SMN2 (PubMed:11074001, PubMed:16601202). The SMN complex may be required for correct assembly of the H/ACA snoRNP complex (PubMed:11074001, PubMed:16601202). Component of the telomerase holoenzyme complex composed of one molecule of TERT, one molecule of WRAP53/TCAB1, two molecules of H/ACA ribonucleoprotein complex subunits DKC1, NOP10, NHP2 and GAR1, and a telomerase RNA template component (TERC) (PubMed:19179534, PubMed:20351177, PubMed:29695869). The telomerase holoenzyme complex is associated with TEP1, SMG6/EST1A and POT1 (PubMed:19179534). Also localized to Cajal bodies (coiled bodies). The disease is caused by variants affecting the gene represented in this entry. Belongs to the NOP10 family.