Seroatlas · Human Serome Atlas

NAPRT

Nicotinate phosphoribosyltransferase

Also known as: NAPRT1, PNCB_HUMAN, PP3856

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

Protein identityUniProt · HPA

UniProt accession
Q6XQN6
Gene
NAPRT
Ensembl
ENSG00000147813
Chromosome
8
Canonical length
538 aa
Protein class
Enzymes, Metabolic proteins, Predicted intracellular proteins
Subcellular location
Nucleoplasm,Golgi apparatus,Cytosol
Quaternary structure
Homodimer

OverviewNCBI Gene

Nicotinic acid (NA; niacin) is converted by nicotinic acid phosphoribosyltransferase (NAPRT; EC 2.4.2.11) to NA mononucleotide (NaMN), which is then converted to NA adenine dinucleotide (NaAD), and finally to nicotinamide adenine dinucleotide (NAD), which serves as a coenzyme in cellular redox reactions and is an essential component of a variety of processes in cellular metabolism including response to stress (Hara et al., 2007).[supplied by OMIM, Mar 2008]

Canonical amino-acid sequenceUniProt

538 residues, UniProt reviewed canonical sequence.

>Q6XQN6|NAPRT
     1  MAAEQDPEAR AAARPLLTDL YQATMALGYW RAGRARDAAE FELFFRRCPF GGAFALAAGL
    61  RDCVRFLRAF RLRDADVQFL ASVLPPDTDP AFFEHLRALD CSEVTVRALP EGSLAFPGVP
   121  LLQVSGPLLV VQLLETPLLC LVSYASLVAT NAARLRLIAG PEKRLLEMGL RRAQGPDGGL
   181  TASTYSYLGG FDSSSNVLAG QLRGVPVAGT LAHSFVTSFS GSEVPPDPML APAAGEGPGV
   241  DLAAKAQVWL EQVCAHLGLG VQEPHPGERA AFVAYALAFP RAFQGLLDTY SVWRSGLPNF
   301  LAVALALGEL GYRAVGVRLD SGDLLQQAQE IRKVFRAAAA QFQVPWLESV LIVVSNNIDE
   361  EALARLAQEG SEVNVIGIGT SVVTCPQQPS LGGVYKLVAV GGQPRMKLTE DPEKQTLPGS
   421  KAAFRLLGSD GSPLMDMLQL AEEPVPQAGQ ELRVWPPGAQ EPCTVRPAQV EPLLRLCLQQ
   481  GQLCEPLPSL AESRALAQLS LSRLSPEHRR LRSPAQYQVV LSERLQALVN SLCAGQSP

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against NAPRT 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)
0.24
Highest tissue expression
103 nTPM

Expression across tissuesHPA

Tissue

  • liver: 103 nTPM
  • esophagus: 65 nTPM
  • duodenum: 58 nTPM
  • small intestine: 45 nTPM
  • skin: 45 nTPM
  • kidney: 37 nTPM

Single-cell type

  • esophageal apical cells: 901 nCPM
  • enterocytes: 505 nCPM
  • colonocytes: 247 nCPM
  • esophageal suprabasal cells: 159 nCPM
  • foveolar cells: 155 nCPM
  • enteric transient amplifying cells: 152 nCPM

Immune cell

  • non-classical monocyte: 23 nTPM
  • eosinophil: 14 nTPM
  • intermediate monocyte: 13 nTPM
  • classical monocyte: 11 nTPM
  • neutrophil: 11 nTPM
  • basophil: 7 nTPM

Brain region

  • white matter: 7.5 nTPM
  • medulla oblongata: 7.3 nTPM
  • hypothalamus: 6.1 nTPM
  • basal ganglia: 5.7 nTPM
  • choroid plexus: 5.6 nTPM
  • spinal cord: 5.5 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)
1.43
gnomAD pLI
0
DepMap mean gene effect
-0.14
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 9% 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

  • Aldolase-type TIM barrel
  • Nicotinate phosphoribosyltransferase-like, C-terminal
  • Nicotinate phosphoribosyltransferase pncB-type
  • Nicotinate phosphoribosyltransferase family
  • Nicotinate phosphoribosyltransferase, N-terminal domain
  • Nicotinate phosphoribosyltransferase C-terminal domain
  • Nicotinate phosphoribosyltransferase (NAPRTase) N-terminal domain
  • Nicotinate phosphoribosyltransferase C-terminal domain

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

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

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

Canonical record: https://seroatlas.com/gene/NAPRT. 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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