Seroatlas · Human Serome Atlas

KLK9

Kallikrein-9

Also known as: KLK-L3, KLK9_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q9UKQ9
Gene
KLK9
Ensembl
ENSG00000213022
Chromosome
19
Canonical length
250 aa
Protein class
Cancer-related genes, Enzymes, Predicted secreted proteins
Secretome location
Secreted in other tissues

OverviewNCBI Gene

The protein encoded by this gene is a kallikrein-related serine protease. This gene is activated by steroid hormones in a human breast cancer cell line, making it a good marker for cancer detection. The encoded protein is found primarily in the cytoplasm.[provided by RefSeq, Oct 2010]

Canonical amino-acid sequenceUniProt

250 residues, UniProt reviewed canonical sequence.

>Q9UKQ9|KLK9
     1  MKLGLLCALL SLLAGHGWAD TRAIGAEECR PNSQPWQAGL FHLTRLFCGA TLISDRWLLT
    61  AAHCRKPYLW VRLGEHHLWK WEGPEQLFRV TDFFPHPGFN KDLSANDHND DIMLIRLPRQ
   121  ARLSPAVQPL NLSQTCVSPG MQCLISGWGA VSSPKALFPV TLQCANISIL ENKLCHWAYP
   181  GHISDSMLCA GLWEGGRGSC QGDSGGPLVC NGTLAGVVSG GAEPCSRPRR PAVYTSVCHY
   241  LDWIQEIMEN

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against KLK9 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
11 nTPM

Expression across tissuesHPA

Tissue

  • skin: 11 nTPM
  • cervix: 6.4 nTPM
  • esophagus: 5 nTPM
  • vagina: 2.3 nTPM
  • tonsil: 1.6 nTPM
  • salivary gland: 0.7 nTPM

Single-cell type

  • adipocytes: 0 nCPM
  • adrenal cortex cells: 0 nCPM
  • adrenal medulla cells: 0 nCPM
  • alveolar cells type 1: 0 nCPM
  • alveolar cells type 2: 0 nCPM
  • astrocytes: 0 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

  • 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)
1.53
gnomAD pLI
0
gnomAD missense Z
0.11
DepMap mean gene effect
0.11
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 8% 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 KLK9 as an antibody target. Whether an autoantibody or antibody against KLK9 could matter depends on whether native KLK9 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

KLK9 is annotated as secreted, so native KLK9 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 KLK9 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/KLK9. 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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