Seroatlas · Human Serome Atlas

RRP9

U3 small nucleolar RNA-interacting protein 2

Also known as: RNU3IP2, U3-55K, U3IP2_HUMAN

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession
O43818
Gene
RRP9
Ensembl
ENSG00000114767
Chromosome
3
Canonical length
475 aa
Protein class
Predicted intracellular proteins
Subcellular location
Nucleoplasm

OverviewNCBI Gene

This gene encodes a member of the WD-repeat protein family. The encoded protein is a component of the nucleolar small nuclear ribonucleoprotein particle (snoRNP) and is essential for 18s rRNA processing during ribosome synthesis. It contains seven WD domains required for nucleolar localization and specific interaction with the U3 small nucleolar RNA (U3 snoRNA). [provided by RefSeq, Oct 2012]

Canonical amino-acid sequenceUniProt

475 residues, UniProt reviewed canonical sequence.

>O43818|RRP9
     1  MSATAAARKR GKPASGAGAG AGAGKRRRKA DSAGDRGKSK GGGKMNEEIS SDSESESLAP
    61  RKPEEEEEEE LEETAQEKKL RLAKLYLEQL RQQEEEKAEA RAFEEDQVAG RLKEDVLEQR
   121  GRLQKLVAKE IQAPASADIR VLRGHQLSIT CLVVTPDDSA IFSAAKDCSI IKWSVESGRK
   181  LHVIPRAKKG AEGKPPGHSS HVLCMAISSD GKYLASGDRS KLILIWEAQS CQHLYTFTGH
   241  RDAVSGLAFR RGTHQLYSTS HDRSVKVWNV AENSYVETLF GHQDAVAALD ALSRECCVTA
   301  GGRDGTVRVW KIPEESQLVF YGHQGSIDCI HLINEEHMVS GADDGSVALW GLSKKRPLAL
   361  QREAHGLRGE PGLEQPFWIS SVAALLNTDL VATGSHSSCV RLWQCGEGFR QLDLLCDIPL
   421  VGFINSLKFS SSGDFLVAGV GQEHRLGRWW RIKEARNSVC IIPLRRVPVP PAAGS

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against RRP9 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability
Intracellular
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.33
Highest tissue expression
28 nTPM

Expression across tissuesHPA

Tissue

  • skeletal muscle: 28 nTPM
  • adipose tissue: 20 nTPM
  • adrenal gland: 20 nTPM
  • esophagus: 18 nTPM
  • skin: 18 nTPM
  • breast: 17 nTPM

Single-cell type

  • basal keratinocytes: 58 nCPM
  • esophageal basal cells: 56 nCPM
  • extravillous trophoblasts: 48 nCPM
  • suprabasal keratinocytes: 45 nCPM
  • migrating cytotrophoblasts: 40 nCPM
  • differentiating spermatogonia: 38 nCPM

Immune cell

  • NK-cell: 19 nTPM
  • plasmacytoid DC: 18 nTPM
  • MAIT T-cell: 18 nTPM
  • myeloid DC: 17 nTPM
  • memory B-cell: 17 nTPM
  • gdT-cell: 16 nTPM

Brain region

  • basal ganglia: 14 nTPM
  • thalamus: 13 nTPM
  • cerebral cortex: 13 nTPM
  • hippocampal formation: 13 nTPM
  • white matter: 13 nTPM
  • medulla oblongata: 12 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)
0.44
gnomAD pLI
0.29
gnomAD missense Z
1.24
DepMap mean gene effect
-0.95
DepMap dependency class
common

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of RRP9 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads RRP9 as an antibody target. Whether an autoantibody or antibody against RRP9 could matter depends on whether native RRP9 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

RRP9 is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label RRP9 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/RRP9. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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