Seroatlas · Human Serome Atlas

POLR3B

DNA-directed RNA polymerase III subunit RPC2

Also known as: C128, FLJ10388, RPC2, RPC2_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q9NW08
Gene: POLR3B
Ensembl: ENSG00000013503
Chromosome: 12
Canonical length: 1133 aa
Protein class: Disease related genes, Enzymes, Human disease related genes, Metabolic proteins, Potential drug targets, Predicted intracellular proteins, RNA polymerase related proteins
Subcellular location: Nuclear speckles

OverviewNCBI Gene

This gene encodes the second largest subunit of RNA polymerase III, the polymerase responsible for synthesizing transfer and small ribosomal RNAs in eukaryotes. The largest subunit and the encoded protein form the catalytic center of RNA polymerase III. Mutations in this gene are a cause of hypomyelinating leukodystrophy. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Dec 2011]

Canonical amino-acid sequenceUniProt

1133 residues, UniProt reviewed canonical sequence.

>Q9NW08|POLR3B
     1  MDVLAEEFGN LTPEQLAAPI PTVEEKWRLL PAFLKVKGLV KQHIDSFNYF INVEIKKIMK
    61  ANEKVTSDAD PMWYLKYLNI YVGLPDVEES FNVTRPVSPH ECRLRDMTYS APITVDIEYT
   121  RGSQRIIRNA LPIGRMPIML RSSNCVLTGK TPAEFAKLNE CPLDPGGYFI VKGVEKVILI
   181  QEQLSKNRII VEADRKGAVG ASVTSSTHEK KSRTNMAVKQ GRFYLRHNTL SEDIPIVIIF
   241  KAMGVESDQE IVQMIGTEEH VMAAFGPSLE ECQKAQIFTQ MQALKYIGNK VRRQRMWGGG
   301  PKKTKIEEAR ELLASTILTH VPVKEFNFRA KCIYTAVMVR RVILAQGDNK VDDRDYYGNK
   361  RLELAGQLLS LLFEDLFKKF NSEMKKIADQ VIPKQRAAQF DVVKHMRQDQ ITNGMVNAIS
   421  TGNWSLKRFK MDRQGVTQVL SRLSYISALG MMTRISSQFE KTRKVSGPRS LQPSQWGMLC
   481  PSDTPEGEAC GLVKNLALMT HITTDMEDGP IVKLASNLGV EDVNLLCGEE LSYPNVFLVF
   541  LNGNILGVIR DHKKLVNTFR LMRRAGYINE FVSISTNLTD RCVYISSDGG RLCRPYIIVK
   601  KQKPAVTNKH MEELAQGYRN FEDFLHESLV EYLDVNEEND CNIALYEHTI NKDTTHLEIE
   661  PFTLLGVCAG LIPYPHHNQS PRNTYQCAMG KQAMGTIGYN QRNRIDTLMY LLAYPQKPMV
   721  KTKTIELIEF EKLPAGQNAT VAVMSYSGYD IEDALVLNKA SLDRGFGRCL VYKNAKCTLK
   781  RYTNQTFDKV MGPMLDAATR KPIWRHEILD ADGICSPGEK VENKQVLVNK SMPTVTQIPL
   841  EGSNVPQQPQ YKDVPITYKG ATDSYIEKVM ISSNAEDAFL IKMLLRQTRR PEIGDKFSSR
   901  HGQKGVCGLI VPQEDMPFCD SGICPDIIMN PHGFPSRMTV GKLIELLAGK AGVLDGRFHY
   961  GTAFGGSKVK DVCEDLVRHG YNYLGKDYVT SGITGEPLEA YIYFGPVYYQ KLKHMVLDKM
  1021  HARARGPRAV LTRQPTEGRS RDGGLRLGEM ERDCLIGYGA SMLLLERLMI SSDAFEVDVC
  1081  GQCGLLGYSG WCHYCKSSCH VSSLRIPYAC KLLFQELQSM NIIPRLKLSK YNE

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against POLR3B 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): 0.26
Highest tissue expression: 11 nTPM

Expression across tissuesHPA

Tissue

skin: 11 nTPM
parathyroid gland: 11 nTPM
liver: 8.4 nTPM
adrenal gland: 8.2 nTPM
esophagus: 8.2 nTPM
tongue: 7.8 nTPM

Single-cell type

cardiomyocytes: 94 nCPM
thymic myoid cells: 65 nCPM
choroid plexus epithelial cells: 53 nCPM
somatotrophs: 49 nCPM
alveolar cells type 1: 48 nCPM
neutrophil progenitors: 47 nCPM

Immune cell

basophil: 5.6 nTPM
naive CD4 T-cell: 3 nTPM
MAIT T-cell: 2.7 nTPM
T-reg: 2.7 nTPM
myeloid DC: 2.6 nTPM
memory CD4 T-cell: 2.3 nTPM

Brain region

cerebellum: 24 nTPM
cerebral cortex: 24 nTPM
basal ganglia: 23 nTPM
white matter: 22 nTPM
choroid plexus: 21 nTPM
hypothalamus: 21 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about POLR3B.

Disease | AllUniProt

Conditions POLR3B is implicated in, by any mechanism.

Leukodystrophy, hypomyelinating, 8, with or without oligodontia and/or hypogonadotropic hypogonadism (HLD8) MIM:614381
Charcot-Marie-Tooth disease, demyelinating, type 1I (CMT1I) MIM:619742

Disease | GeneticClinVar

74 pathogenic / likely-pathogenic of 771 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

Hypomyelinating leukodystrophy 8 with or without oligodontia and-or hypogonadotropic hypogonadism
Charcot-Marie-Tooth disease, demyelinating, IIA 1I
POLR3B-related disorder
Thyroid cancer, nonmedullary, 1
POLR-related leukodystrophy

Disease | ImmuneIEDB

Conditions an epitope on POLR3B was assayed in.

systemic scleroderma B cell

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): 0.87
gnomAD pLI: 0
gnomAD missense Z: 3.2
DepMap mean gene effect: -1.97
DepMap dependency class: pan

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 6% 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 POLR3B 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 POLR3B as an antibody target. Whether an autoantibody or antibody against POLR3B could matter depends on whether native POLR3B is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

POLR3B 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 POLR3B as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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