Seroatlas · Human Serome Atlas

CST5

Cystatin-D

Also known as: CYTD_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P28325
Gene
CST5
Ensembl
ENSG00000170367
Chromosome
20
Canonical length
142 aa
Protein class
Plasma proteins, Predicted secreted proteins
Secretome location
Secreted to digestive 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. 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 protein found in saliva and tears. The encoded protein may play a protective role against proteinases present in the oral cavity. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

142 residues, UniProt reviewed canonical sequence.

>P28325|CST5
     1  MMWPMHTPLL LLTALMVAVA GSASAQSRTL AGGIHATDLN DKSVQCALDF AISEYNKVIN
    61  KDEYYSRPLQ VMAAYQQIVG GVNYYFNVKF GRTTCTKSQP NLDNCPFNDQ PKLKEEEFCS
   121  FQINEVPWED KISILNYKCR KV

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CST5 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)
0.39
Highest tissue expression
2,026 nTPM

Expression across tissuesHPA

Tissue

  • salivary gland: 2,026 nTPM
  • pancreas: 2.1 nTPM
  • smooth muscle: 1.4 nTPM
  • lung: 1.2 nTPM
  • adrenal gland: 0.9 nTPM
  • heart muscle: 0.4 nTPM

Single-cell type

  • salivary acinar cells: 462 nCPM
  • salivary myoepithelial cells: 67 nCPM
  • epididymal efferent duct absorptive cells: 24 nCPM
  • neutrophils: 12 nCPM
  • lacrimal acinar cells: 8.2 nCPM
  • salivary duct cells: 5 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
-1.34
DepMap mean gene effect
0.08
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

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads CST5 as an antibody target. Whether an autoantibody or antibody against CST5 could matter depends on whether native CST5 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CST5 is annotated as secreted, so native CST5 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 CST5 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/CST5. 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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