H/ACA small nucleolar ribonucleoprotein complex (H/ACA snoRNP complex)

Function: - 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 residues, which may serve to stabilize the conformation of rRNAs - binds a box H/ACA small nucleolar RNA (snoRNA), which may target the specific site of modification within the RNA substrate - interacts with TERC, which contains a 3'-terminal domain related to the box H/ACA snoRNAs - specific interactions with snoRNAs or TERC are mediated by NOLA1 & NOLA2 - H/ACA snoRNPs interact with the SMN complex - this is mediated by interaction between GAR1 & SMN1 or SMN2 - SMN complex may be required for correct assembly of the H/ACA snoRNP complex - complex contains a stable core formed by binding of 1 or 2 NOLA3-DKC1 heterodimers to NOLA2 - NOLA1 subsequently binds to this core via DKC1 Structure: - subunits: NOLA1, NOLA2, NOLA3, DKC1 (NOLA4) - DKC1 is presumed to be the catalytic subunit

Properties

SUBUNITS: nucleolar protein family A member 1 COMPARTMENT: cell nucleus MOTIF: RGG-box 1 {4-57} RGG-box 2 {169-217} H/ACA ribonucleoprotein complex subunit 2 COMPARTMENT: cell nucleus ribosome biogenesis protein Nop10 COMPARTMENT: cell nucleus H/ACA ribonucleoprotein complex subunit 4 COMPARTMENT: cell nucleus MOTIF: Nucleolar localization {2-21} acetylation site SITE: N-TERMINUS EFFECTOR-BOUND: acetyl lysine-rich region {11-17} MOTIF: lysine residue (SEVERAL) Ser phosphorylation site {S21} aspartate residue {D125} PUA {296-371} Ser phosphorylation site {S422} Nuclear and nucleolar localization {446-514} MOTIF: Ser phosphorylation site {S451} Ser phosphorylation site {S453} Ser phosphorylation site {S455} Thr phosphorylation site {T458} Ser phosphorylation site {S485} Ser phosphorylation site {S494} Thr phosphorylation site {T496} Thr phosphorylation site {T497} Ser phosphorylation site {S513}

References

UniProt :accession Q9NX24

Components

H/ACA ribonucleoprotein complex subunit 2 (nucleolar protein family A member 2, snoRNP protein NHP2, NOLA2, NHP2, HSPC286) H/ACA ribonucleoprotein complex subunit 4; dyskerin; nucleolar protein family A member 4; snoRNP protein DKC1; Nopp140-associated protein of 57 kDa; nucleolar protein NAP57; CBF5 homolog (DKC1, NOLA4) nucleolar protein family A member 1; H/ACA ribonucleoprotein complex subunit 1; nucleolar protein family A member 1; snoRNP protein GAR1 (GAR1, NOLA1) ribosome biogenesis protein Nop10; H/ACA ribonucleoprotein complex subunit 3; snoRNP protein NOP10; nucleolar protein family A member 3 (NOP10, NOLA3)