SMR3A
Submaxillary gland androgen-regulated protein 3A
Also known as: PBI, PRL5, PROL5, SMR3A_HUMAN
Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene
Protein identityUniProt · HPA
- UniProt accession
- Q99954
- Gene
- SMR3A
- Ensembl
- ENSG00000109208
- Chromosome
- 4
- Canonical length
- 134 aa
- Protein class
- Predicted secreted proteins
- Secretome location
- Secreted to digestive system
OverviewNCBI Gene
Predicted to enable endopeptidase inhibitor activity. Predicted to be involved in regulation of sensory perception of pain. Predicted to be located in extracellular region. [provided by Alliance of Genome Resources, Jul 2025]
Canonical amino-acid sequenceUniProt
134 residues, UniProt reviewed canonical sequence.
>Q99954|SMR3A
1 MKSLTWILGL WALAACFTPG ESQRGPRGPY PPGPLAPPPP PCFPFGTGFV PPPHPPPYGP
61 GRFPPPLSPP YGPGRIPPSP PPPYGPGRIQ SHSLPPPYGP GYPQPPSQPR PYPPGPPFFP
121 VNSPTDPALP TPAPLocalizationUniProt · AlphaFold · HPA
Whether an antibody against SMR3A 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)
- 0.65
- Highest tissue expression
- 56 nTPM
Expression across tissuesHPA
Tissue
- salivary gland: 56 nTPM
- thyroid gland: 0.9 nTPM
- prostate: 0.2 nTPM
- esophagus: 0.1 nTPM
- adipose tissue: 0 nTPM
- adrenal gland: 0 nTPM
Single-cell type
- lacrimal acinar cells: 2,832 nCPM
- salivary acinar cells: 112 nCPM
- submucosal glandular cells: 15 nCPM
- conjunctival goblet cells: 13 nCPM
- ocular epithelial cells: 9.9 nCPM
- epididymal efferent duct ciliated cells: 4.2 nCPM
Immune cell
- basophil: 0 nTPM
- classical monocyte: 0 nTPM
- eosinophil: 0 nTPM
- gdT-cell: 0 nTPM
- intermediate monocyte: 0 nTPM
- MAIT T-cell: 0 nTPM
Brain region
- midbrain: 1.2 nTPM
- thalamus: 0.4 nTPM
- hypothalamus: 0.1 nTPM
- amygdala: 0 nTPM
- basal ganglia: 0 nTPM
- cerebellum: 0 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)
- 1.73
- gnomAD pLI
- 0.39
- gnomAD missense Z
- -0.59
- DepMap mean gene effect
- 0.02
- DepMap dependency class
- none
Cancer expressionTCGA
Across TCGA tumor cohorts, this protein is over-expressed in roughly 2% 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 SMR3A as an antibody target. Whether an autoantibody or antibody against SMR3A could matter depends on whether native SMR3A is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.
SMR3A is annotated as secreted, so native SMR3A 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 SMR3A as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.
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