Seroatlas · Human Serome Atlas

SERPINA4

Kallistatin

Also known as: KAIN_HUMAN, KAL, KLST, KST, PI4

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

Protein identityUniProt · HPA

UniProt accession: P29622
Gene: SERPINA4
Ensembl: ENSG00000100665
Chromosome: 14
Canonical length: 427 aa
Protein class: Plasma proteins, Predicted secreted proteins
Subcellular location: Vesicles
Secretome location: Secreted to blood
Quaternary structure: Homodimer

OverviewNCBI Gene

Predicted to enable serine-type endopeptidase inhibitor activity. Located in extracellular exosome. Biomarker of diabetic retinopathy. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

427 residues, UniProt reviewed canonical sequence.

>P29622|SERPINA4
     1  MHLIDYLLLL LVGLLALSHG QLHVEHDGES CSNSSHQQIL ETGEGSPSLK IAPANADFAF
    61  RFYYLIASET PGKNIFFSPL SISAAYAMLS LGACSHSRSQ ILEGLGFNLT ELSESDVHRG
   121  FQHLLHTLNL PGHGLETRVG SALFLSHNLK FLAKFLNDTM AVYEAKLFHT NFYDTVGTIQ
   181  LINDHVKKET RGKIVDLVSE LKKDVLMVLV NYIYFKALWE KPFISSRTTP KDFYVDENTT
   241  VRVPMMLQDQ EHHWYLHDRY LPCSVLRMDY KGDATVFFIL PNQGKMREIE EVLTPEMLMR
   301  WNNLLRKRNF YKKLELHLPK FSISGSYVLD QILPRLGFTD LFSKWADLSG ITKQQKLEAS
   361  KSFHKATLDV DEAGTEAAAA TSFAIKFFSA QTNRHILRFN RPFLVVIFST STQSVLFLGK
   421  VVDPTKP

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SERPINA4 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: 514 nTPM

Expression across tissuesHPA

Tissue

liver: 514 nTPM
pancreas: 125 nTPM
gallbladder: 50 nTPM
epididymis: 39 nTPM
stomach: 26 nTPM
kidney: 6.8 nTPM

Single-cell type

cholangiocytes: 12 nCPM
hepatocytes: 9.4 nCPM
parietal cells: 7.1 nCPM
mucous neck cells: 2.4 nCPM
gastric chief cells: 2.2 nCPM
pancreatic duct cells: 2.2 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

medulla oblongata: 0.2 nTPM
amygdala: 0.1 nTPM
basal ganglia: 0.1 nTPM
choroid plexus: 0.1 nTPM
hippocampal formation: 0.1 nTPM
hypothalamus: 0.1 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): 1.66
gnomAD pLI: 0
gnomAD missense Z: -0.68
DepMap mean gene effect: -0.04
DepMap dependency class: selective

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

Molecular functions

serine-type endopeptidase inhibitor activity

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SERPINA4 as an antibody target. Whether an autoantibody or antibody against SERPINA4 could matter depends on whether native SERPINA4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SERPINA4 is annotated as secreted, so native SERPINA4 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 SERPINA4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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