Seroatlas · Human Serome Atlas

CST9

Cystatin-9

Also known as: CLM, CST9_HUMAN, CTES7A

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

Protein identityUniProt · HPA

UniProt accession: Q5W186
Gene: CST9
Ensembl: ENSG00000173335
Chromosome: 20
Canonical length: 159 aa
Protein class: Predicted secreted proteins
Secretome location: Secreted in female reproductive system

OverviewNCBI Gene

The cystatin superfamily encompasses proteins that contain multiple cystatin-like sequences. Some of the members are active cysteine protease inhibitors, while others have lost or perhaps never acquired this inhibitory activity. There are three inhibitory families in the superfamily, including the type 1 cystatins (stefins), type 2 cystatins and the kininogens. The type 2 cystatin proteins are a class of cysteine proteinase inhibitors found in a variety of human fluids and secretions, where they appear to provide protective functions. The cystatin locus on chromosome 20 contains the majority of the type 2 cystatin genes and pseudogenes. This gene is located in the cystatin locus and encodes a secreted protein that may play a role in hematopoietic differentiation or inflammation. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

159 residues, UniProt reviewed canonical sequence.

>Q5W186|CST9
     1  MSSPQRRKAM PWALSLLLMG FQLLVTYAWC SEEEMGGNNK IVQDPMFLAT VEFALNTFNV
    61  QSKEEHAYRL LRVLSSWRED SMDRKWRGKM VFSMNLQLRQ TVCRKFEDDI DNCPFQESLE
   121  LNNVRQGISF PQVHSCGCCM GCGVGTGAAD KAIPRDKGK

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CST9 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): 0.47
Highest tissue expression: 1.5 nTPM

Expression across tissuesHPA

Tissue

breast: 1.5 nTPM
kidney: 0.1 nTPM
adipose tissue: 0 nTPM
adrenal gland: 0 nTPM
amygdala: 0 nTPM
appendix: 0 nTPM

Single-cell type

epididymal principal cells: 3.7 nCPM
breast hormone-responsive cells: 1 nCPM
breast myoepithelial cells: 0.9 nCPM
esophageal apical cells: 0.8 nCPM
epididymal efferent duct absorptive cells: 0.2 nCPM
undifferentiated spermatogonia: 0.1 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): 1.89
gnomAD pLI: 0
gnomAD missense Z: -0.21
DepMap mean gene effect: 0.14
DepMap dependency class: none

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

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads CST9 as an antibody target. Whether an autoantibody or antibody against CST9 could matter depends on whether native CST9 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CST9 is annotated as secreted, so native CST9 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 CST9 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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