Seroatlas · Human Serome Atlas

SPINK9

Serine protease inhibitor Kazal-type 9

Also known as: ISK9_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q5DT21
Gene
SPINK9
Ensembl
ENSG00000204909
Chromosome
5
Canonical length
86 aa
Protein class
Predicted intracellular proteins, Predicted secreted proteins
Subcellular location
Nucleoplasm,Vesicles
Secretome location
Secreted in other tissues

OverviewNCBI Gene

The protein encoded by this gene is a Kazal-type serine protease inhibitor that appears to specifically target kallikrein-related peptidase 5 (KLK5) in the palmo-plantar epidermis. KLK5 is an important initiator of skin desquamation, so the encoded protease inhibitor may regulate skin differentiation in the palms of hands and soles of feet. This cationic protein has also been shown to promote keratinocyte migration by activation of the epidermal growth factor receptor (EGFR). [provided by RefSeq, Dec 2015]

Canonical amino-acid sequenceUniProt

86 residues, UniProt reviewed canonical sequence.

>Q5DT21|SPINK9
     1  MRATAIVLLL ALTLATMFSI ECAKQTKQMV DCSHYKKLPP GQQRFCHHMY DPICGSDGKT
    61  YKNDCFFCSK VKKTDGTLKF VHFGKC

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SPINK9 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)
0.42
Highest tissue expression
2.6 nTPM

Expression across tissuesHPA

Tissue

  • thymus: 2.6 nTPM
  • bone marrow: 2.3 nTPM
  • retina: 2 nTPM
  • skeletal muscle: 0.9 nTPM
  • testis: 0.8 nTPM
  • skin: 0.7 nTPM

Single-cell type

  • cardiomyocytes: 91 nCPM
  • epicardial cells: 18 nCPM
  • myonuclei: 6.6 nCPM
  • adipocytes: 4.8 nCPM
  • renal connecting tubule cells: 4.8 nCPM
  • podocytes: 4.1 nCPM

Immune cell

  • basophil: 6.4 nTPM
  • neutrophil: 2.2 nTPM
  • non-classical monocyte: 1.4 nTPM
  • memory CD8 T-cell: 0.7 nTPM
  • naive CD4 T-cell: 0.7 nTPM
  • plasmacytoid DC: 0.7 nTPM

Brain region

  • cerebral cortex: 34 nTPM
  • white matter: 32 nTPM
  • amygdala: 30 nTPM
  • cerebellum: 30 nTPM
  • hippocampal formation: 30 nTPM
  • basal ganglia: 29 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)
1.6
gnomAD pLI
0.02
gnomAD missense Z
0.26
DepMap mean gene effect
0.1
DepMap dependency class
none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% 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

InteractionsUniProt · HPA

Protein binding partners of SPINK9 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SPINK9 as an antibody target. Whether an autoantibody or antibody against SPINK9 could matter depends on whether native SPINK9 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SPINK9 is annotated as secreted, so native SPINK9 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 SPINK9 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/SPINK9. 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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