Seroatlas · Human Serome Atlas

CTSB

Cathepsin B

Also known as: CATB_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P07858
Gene
CTSB
Ensembl
ENSG00000164733
Chromosome
8
Canonical length
339 aa
Protein class
Cancer-related genes, Candidate cardiovascular disease genes, Disease related genes, Enzymes, Human disease related genes, Metabolic proteins, Plasma proteins, Potential drug targets, Predicted intracellular proteins, Predicted secreted proteins
Subcellular location
Nucleoli,Vesicles
Secretome location
Secreted to blood

OverviewNCBI Gene

This gene encodes a member of the C1 family of peptidases. Alternative splicing of this gene results in multiple transcript variants. At least one of these variants encodes a preproprotein that is proteolytically processed to generate multiple protein products. These products include the cathepsin B light and heavy chains, which can dimerize to form the double chain form of the enzyme. This enzyme is a lysosomal cysteine protease with both endopeptidase and exopeptidase activity that may play a role in protein turnover. It is also known as amyloid precursor protein secretase and is involved in the proteolytic processing of amyloid precursor protein (APP). Incomplete proteolytic processing of APP has been suggested to be a causative factor in Alzheimer's disease, the most common cause of dementia. Overexpression of the encoded protein has been associated with esophageal adenocarcinoma and other tumors. Both Cathepsin B and Cathepsin L are involved in the cleavage of the spike protein from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) upon its entry to the human host cell. Multiple pseudogenes of this gene have been identified. [provided by RefSeq, Sep 2020]

Canonical amino-acid sequenceUniProt

339 residues, UniProt reviewed canonical sequence.

>P07858|CTSB
     1  MWQLWASLCC LLVLANARSR PSFHPLSDEL VNYVNKRNTT WQAGHNFYNV DMSYLKRLCG
    61  TFLGGPKPPQ RVMFTEDLKL PASFDAREQW PQCPTIKEIR DQGSCGSCWA FGAVEAISDR
   121  ICIHTNAHVS VEVSAEDLLT CCGSMCGDGC NGGYPAEAWN FWTRKGLVSG GLYESHVGCR
   181  PYSIPPCEHH VNGSRPPCTG EGDTPKCSKI CEPGYSPTYK QDKHYGYNSY SVSNSEKDIM
   241  AEIYKNGPVE GAFSVYSDFL LYKSGVYQHV TGEMMGGHAI RILGWGVENG TPYWLVANSW
   301  NTDWGDNGFF KILRGQDHCG IESEVVAGIP RTDQYWEKI

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CTSB 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
Cell surface
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.25
Highest tissue expression
991 nTPM

Expression across tissuesHPA

Tissue

  • thyroid gland: 991 nTPM
  • liver: 440 nTPM
  • cervix: 410 nTPM
  • urinary bladder: 403 nTPM
  • appendix: 378 nTPM
  • spleen: 349 nTPM

Single-cell type

  • kupffer cells: 1,673 nCPM
  • hofbauer cells: 627 nCPM
  • macrophages: 438 nCPM
  • esophageal apical cells: 410 nCPM
  • monocytes: 390 nCPM
  • microglia: 370 nCPM

Immune cell

  • total PBMC: 703 nTPM
  • classical monocyte: 611 nTPM
  • intermediate monocyte: 468 nTPM
  • plasmacytoid DC: 411 nTPM
  • basophil: 390 nTPM
  • non-classical monocyte: 309 nTPM

Brain region

  • thalamus: 437 nTPM
  • white matter: 320 nTPM
  • pons: 212 nTPM
  • medulla oblongata: 198 nTPM
  • choroid plexus: 196 nTPM
  • hypothalamus: 185 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about CTSB.

Disease | AllUniProt

Conditions CTSB is implicated in, by any mechanism.

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)
1.33
gnomAD pLI
0
gnomAD missense Z
-3.35
DepMap mean gene effect
0.07
DepMap dependency class
selective

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

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

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

CTSB is annotated at the cell surface, where native CTSB is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label CTSB as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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