Seroatlas · Human Serome Atlas

PRB3

Basic salivary proline-rich protein 3

Also known as: PRB3_HUMAN, PRG

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

Protein identityUniProt · HPA

UniProt accession: Q04118
Gene: PRB3
Ensembl: ENSG00000197870
Chromosome: 12
Canonical length: 351 aa
Protein class: Predicted secreted proteins
Secretome location: Secreted to digestive system

OverviewNCBI Gene

This gene encodes a member of the heterogeneous family of basic, proline-rich, human salivary glycoproteins. Multiple alleles of this gene exhibiting variations in the length of the tandem repeats have been identified. The reference genome encodes the """"""""""""""""""""""""""""""""Long"""""""""""""""""""""""""""""""" allele. The protein isoforms encoded by this gene are recognized as the """"""""""""""""""""""""""""""""first line of oral defense"""""""""""""""""""""""""""""""" against the detrimental effects of polyphenols in the diet and pathogen infections. This gene is located in a cluster of closely related salivary proline-rich proteins on chromosome 12. [provided by RefSeq, Nov 2015]

Canonical amino-acid sequenceUniProt

351 residues, UniProt reviewed canonical sequence.

>Q04118|PRB3
     1  MLLILLSVAL LALSSAQSLN EDVSQEESPS VISGKPEGRR PQGGNQPQRT PPPPGKPEGR
    61  PPQGGNQSQG PPPRPGKPEG PPPQGGNQSQ GPPPRPGKPE GQPPQGGNQS QGPPPRPGKP
   121  EGPPPQGGNQ SQGPPPRPGK PEGPPPQGGN QSQGPPPRPG KPEGPPPQGG NQSQGPPPHP
   181  GKPEGPPPQG GNQSQGPPPR PGKPEGPPPQ GGNQSQGPPP RPGKPEGPPP QGGNKPQGPP
   241  PRPGKPEGPP PQGGNQSQGP PPRPGKPEGP PSQGGNKPQG PPPHPGKPQG PPPQEGNKPQ
   301  RPPPPGRPQG PPPPGGNPQQ PLPPPAGKPQ GPPPPPQGGR PHRPPQGQPP Q

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PRB3 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: Secreted
Secreted: Yes
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.75
Highest tissue expression: 13,017 nTPM

Expression across tissuesHPA

Tissue

salivary gland: 13,017 nTPM
lung: 6.7 nTPM
bone marrow: 1.2 nTPM
skin: 1 nTPM
testis: 1 nTPM
esophagus: 0.1 nTPM

Single-cell type

salivary acinar cells: 13,838 nCPM
salivary myoepithelial cells: 4,670 nCPM
neutrophils: 640 nCPM
submucosal glandular cells: 443 nCPM
t-cells: 143 nCPM
monocytes: 94 nCPM

Immune cell

naive CD4 T-cell: 0.1 nTPM
basophil: 0 nTPM
classical monocyte: 0 nTPM
eosinophil: 0 nTPM
gdT-cell: 0 nTPM
intermediate monocyte: 0 nTPM

Brain region

cerebral cortex: 0.3 nTPM
medulla oblongata: 0.3 nTPM
white matter: 0.3 nTPM
basal ganglia: 0.2 nTPM
choroid plexus: 0.2 nTPM
hippocampal formation: 0.2 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about PRB3.

Disease | GeneticClinVar

2 pathogenic / likely-pathogenic of 66 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

PRB3S(CYS)
PRB3M(NULL)

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): 1.31
gnomAD pLI: 0
gnomAD missense Z: -0.99

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

defense response to Gram-negative bacterium

Cellular components

extracellular region

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads PRB3 as an antibody target. Whether an autoantibody or antibody against PRB3 could matter depends on whether native PRB3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

PRB3 is annotated as secreted, so native PRB3 circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

The present source text does not explicitly label PRB3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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