Seroatlas · Human Serome Atlas

SPINT3

Kunitz-type protease inhibitor 3

Also known as: HKIB9, SPIT3_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P49223
Gene
SPINT3
Ensembl
ENSG00000101446
Chromosome
20
Canonical length
89 aa
Protein class
Predicted secreted proteins
Secretome location
Secreted in male reproductive system

OverviewNCBI Gene

Predicted to enable serine-type endopeptidase inhibitor activity. Predicted to be located in extracellular region. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

89 residues, UniProt reviewed canonical sequence.

>P49223|SPINT3
     1  MQLQASLSFL LILTLCLELR SELARDTIKD LLPNVCAFPM EKGPCQTYMT RWFFNFETGE
    61  CELFAYGGCG GNSNNFLRKE KCEKFCKFT

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SPINT3 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)
0.4
Highest tissue expression
10 nTPM

Expression across tissuesHPA

Tissue

  • seminal vesicle: 10 nTPM
  • epididymis: 4.5 nTPM
  • skin: 1.2 nTPM
  • prostate: 0.1 nTPM
  • adipose tissue: 0 nTPM
  • adrenal gland: 0 nTPM

Single-cell type

  • epididymal principal cells: 19 nCPM
  • endometrial luminal cells: 10 nCPM
  • salivary basal cells: 2.9 nCPM
  • epididymal clear cells: 2 nCPM
  • endometrial glandular cells: 1.9 nCPM
  • basal prostatic cells: 1.8 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

  • cerebral cortex: 1.5 nTPM
  • white matter: 1.1 nTPM
  • hippocampal formation: 0.7 nTPM
  • basal ganglia: 0.6 nTPM
  • pons: 0.5 nTPM
  • amygdala: 0.4 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)
1.92
gnomAD pLI
0.02
gnomAD missense Z
0.42
DepMap mean gene effect
0.08
DepMap dependency class
selective

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

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SPINT3 as an antibody target. Whether an autoantibody or antibody against SPINT3 could matter depends on whether native SPINT3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SPINT3 is annotated as secreted, so native SPINT3 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 SPINT3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/SPINT3. 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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