Seroatlas · Human Serome Atlas

SERPINA9

Serpin A9

Also known as: GCET1, SERPINA11b, SPA9_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q86WD7
Gene: SERPINA9
Ensembl: ENSG00000170054
Chromosome: 14
Canonical length: 417 aa
Protein class: Predicted intracellular proteins, Predicted secreted proteins
Secretome location: Secreted to blood

OverviewNCBI Gene

Enables serine-type endopeptidase inhibitor activity. Predicted to be located in cytoplasm; extracellular region; and membrane. Predicted to be active in extracellular space. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

417 residues, UniProt reviewed canonical sequence.

>Q86WD7|SERPINA9
     1  MASYLYGVLF AVGLCAPIYC VSPANAPSAY PRPSSTKSTP ASQVYSLNTD FAFRLYRRLV
    61  LETPSQNIFF SPVSVSTSLA MLSLGAHSVT KTQILQGLGF NLTHTPESAI HQGFQHLVHS
   121  LTVPSKDLTL KMGSALFVKK ELQLQANFLG NVKRLYEAEV FSTDFSNPSI AQARINSHVK
   181  KKTQGKVVDI IQGLDLLTAM VLVNHIFFKA KWEKPFHPEY TRKNFPFLVG EQVTVHVPMM
   241  HQKEQFAFGV DTELNCFVLQ MDYKGDAVAF FVLPSKGKMR QLEQALSART LRKWSHSLQK
   301  RWIEVFIPRF SISASYNLET ILPKMGIQNV FDKNADFSGI AKRDSLQVSK ATHKAVLDVS
   361  EEGTEATAAT TTKFIVRSKD GPSYFTVSFN RTFLMMITNK ATDGILFLGK VENPTKS

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SERPINA9 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): 0.28
Highest tissue expression: 68 nTPM

Expression across tissuesHPA

Tissue

tonsil: 68 nTPM
lymph node: 39 nTPM
appendix: 12 nTPM
epididymis: 3.7 nTPM
skin: 1.7 nTPM
thymus: 1.3 nTPM

Single-cell type

b-cells: 2.2 nCPM
innate lymphoid cells: 0.7 nCPM
foveolar cells: 0.4 nCPM
basal prostatic cells: 0.3 nCPM
breast hormone-responsive cells: 0.2 nCPM
epididymal principal cells: 0.1 nCPM

Immune cell

non-classical monocyte: 0.1 nTPM
basophil: 0 nTPM
classical monocyte: 0 nTPM
eosinophil: 0 nTPM
gdT-cell: 0 nTPM
intermediate monocyte: 0 nTPM

Brain region

amygdala: 0 nTPM
basal ganglia: 0 nTPM
cerebellum: 0 nTPM
cerebral cortex: 0 nTPM
choroid plexus: 0 nTPM
hippocampal formation: 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): 1.89
gnomAD pLI: 0
gnomAD missense Z: -1.11
DepMap mean gene effect: 0.06
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

Molecular functions

serine-type endopeptidase inhibitor activity

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SERPINA9 as an antibody target. Whether an autoantibody or antibody against SERPINA9 could matter depends on whether native SERPINA9 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SERPINA9 is annotated as secreted, so native SERPINA9 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 SERPINA9 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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