NHP2

NHP2 is a protein encoded by the NHP2 gene in humans. It is a highly conserved component of H/ACA small nucleolar ribonucleoproteins (snoRNPs) and of the telomerase ribonucleoprotein complex. In the H/ACA RNP, NHP2 partners with the catalytic pseudouridine synthase dyskerin (DKC1) and the core proteins GAR1 and NOP10 to form the four-subunit core that associates with H/ACA guide RNAs.

Functionally, NHP2 contributes to the recognition and binding of H/ACA snoRNAs and is involved in the maturation and stability of snoRNPs, enabling site-specific pseudouridylation of ribosomal RNA and small nuclear RNAs. In the context of telomerase, NHP2 is reported to interact with the telomerase RNA component (TERC) and support assembly and activity of the holoenzyme, thereby contributing to telomere maintenance.

Localization of NHP2 is mainly to the nucleolus and the nucleus, consistent with its roles in rRNA modification and RNA processing.

Clinical significance of NHP2 relates to its involvement in the larger complex of H/ACA RNPs. Mutations or dysregulation of NHP2 and other H/ACA RNP components have been associated with telomere biology disorders such as dyskeratosis congenita and related ribosome biogenesis defects. The gene is studied as part of the broader telomere maintenance and ribosome biosynthesis pathways.

In model organisms, the yeast homolog Nhp2p is an essential component of the H/ACA snoRNPs and is required for pseudouridylation and snoRNP assembly, providing a conserved view of NHP2’s core cellular roles.