GAR1 (GAR1 ribonucleoprotein) is an essential component of the H/ACA small nucleolar ribonucleoprotein (H/ACA snoRNP) complex, which catalyzes pseudouridylation of ribosomal RNA 1. As one of four core proteins in the H/ACA complex alongside Cbf5, Nop10, and Nhp2, GAR1 plays a critical structural role in RNA-guided pseudouridylation, enabling the isomerization of uridine residues in rRNA 2. Each rRNA can contain up to 100 pseudouridine residues that stabilize rRNA conformation and function 1. Beyond ribosome biogenesis, GAR1 is required for telomere maintenance as a component of telomerase-associated H/ACA complexes and contains a SUMO-interacting motif essential for proper dyskerin localization and telomerase RNA interaction 3. Recent evidence demonstrates that the H/ACA snoRNA snR30, bound by the Cbf5-Gar1-Nop10-Nhp2 complex, coordinates independent assembly of the pre-18S rRNA central domain during early ribosome biogenesis 4. GAR1 also interacts with SMN protein, suggesting involvement in snoRNP biogenesis and metabolism 5. Mutations affecting GAR1-containing complexes are implicated in dyskeratosis congenita, a telomere maintenance disorder 6, highlighting its clinical significance in human disease.