PGA3
Pepsin A-3
Also known as: PEPA3_HUMAN
Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene
Protein identityUniProt · HPA
- UniProt accession
- P0DJD8
- Gene
- PGA3
- Ensembl
- ENSG00000229859
- Chromosome
- 11
- Canonical length
- 388 aa
- Protein class
- Enzymes, Predicted intracellular proteins, Predicted secreted proteins
- Secretome location
- Secreted to digestive system
OverviewNCBI Gene
This gene encodes a protein precursor of the digestive enzyme pepsin, a member of the peptidase A1 family of endopeptidases. The encoded precursor is secreted by gastric chief cells and undergoes autocatalytic cleavage in acidic conditions to form the active enzyme, which functions in the digestion of dietary proteins. This gene is found in a cluster of related genes on chromosome 11, each of which encodes one of multiple pepsinogens. Pepsinogen levels in serum may serve as a biomarker for atrophic gastritis and gastric cancer. [provided by RefSeq, Jul 2015]
Canonical amino-acid sequenceUniProt
388 residues, UniProt reviewed canonical sequence.
>P0DJD8|PGA3
1 MKWLLLLGLV ALSECIMYKV PLIRKKSLRR TLSERGLLKD FLKKHNLNPA RKYFPQWKAP
61 TLVDEQPLEN YLDMEYFGTI GIGTPAQDFT VVFDTGSSNL WVPSVYCSSL ACTNHNRFNP
121 EDSSTYQSTS ETVSITYGTG SMTGILGYDT VQVGGISDTN QIFGLSETEP GSFLYYAPFD
181 GILGLAYPSI SSSGATPVFD NIWNQGLVSQ DLFSVYLSAD DQSGSVVIFG GIDSSYYTGS
241 LNWVPVTVEG YWQITVDSIT MNGEAIACAE GCQAIVDTGT SLLTGPTSPI ANIQSDIGAS
301 ENSDGDMVVS CSAISSLPDI VFTINGVQYP VPPSAYILQS EGSCISGFQG MNLPTESGEL
361 WILGDVFIRQ YFTVFDRANN QVGLAPVALocalizationUniProt · AlphaFold · HPA
Whether an antibody against PGA3 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)
- 0.24
- Highest tissue expression
- 63,358 nTPM
Expression across tissuesHPA
Tissue
- stomach: 63,358 nTPM
- esophagus: 70 nTPM
- breast: 12 nTPM
- pancreas: 9.3 nTPM
- liver: 8.3 nTPM
- adipose tissue: 8.1 nTPM
Single-cell type
- gastric chief cells: 2,960 nCPM
- parietal cells: 629 nCPM
- mucous neck cells: 331 nCPM
- foveolar cells: 40 nCPM
- neuroendocrine cells: 12 nCPM
- mast cells: 2.6 nCPM
Immune cell
- intermediate monocyte: 1.3 nTPM
- total PBMC: 1.3 nTPM
- classical monocyte: 0.8 nTPM
- gdT-cell: 0.7 nTPM
- memory CD8 T-cell: 0.7 nTPM
- naive CD8 T-cell: 0.6 nTPM
Brain region
- hippocampal formation: 8 nTPM
- cerebral cortex: 4 nTPM
- cerebellum: 3.6 nTPM
- amygdala: 3.3 nTPM
- basal ganglia: 2.6 nTPM
- white matter: 2.2 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)
- 1.25
- gnomAD pLI
- 0.1
- gnomAD missense Z
- 1.14
Cancer expressionTCGA
Across TCGA tumor cohorts, this protein is over-expressed in roughly 1% 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
Antibody and autoantibody relevanceSeroatlas analysis
Seroatlas reads PGA3 as an antibody target. Whether an autoantibody or antibody against PGA3 could matter depends on whether native PGA3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.
PGA3 is annotated as secreted, so native PGA3 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 PGA3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.
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