Cathepsin K

Cathepsin K

Ribbon diagram of cathepsin K, colored by secondary structure. From PDB 1TU6.
Identifiers
Symbols CTSK; CTS02; CTSO; CTSO1; CTSO2; MGC23107; PKND; PYCD
External IDs OMIM601105 MGI107823 HomoloGene68053 GeneCards: CTSK Gene
EC number 3.4.22.38
RNA expression pattern
More reference expression data
Orthologs
Species Human Mouse
Entrez 1513 13038
Ensembl ENSG00000143387 ENSMUSG00000028111
UniProt P43235 Q545T0
RefSeq (mRNA) NM_000396.3 NM_007802.3
RefSeq (protein) NP_000387.1 NP_031828.2
Location (UCSC) Chr 1:
150.77 – 150.78 Mb
Chr 3:
95.3 – 95.31 Mb
PubMed search [1] [2]

Cathepsin K, abbreviated CTSK, is an enzyme which in humans is encoded by the CTSK gene.[1][2]

Contents

Function

The protein encoded by this gene is a lysosomal cysteine protease involved in bone remodeling and resorption. This protein, which is a member of the peptidase C1 protein family, is predominantly expressed in osteoclasts.

Cathepsin K is a protease, which is defined by its high specificity for kinins, that is involved in bone resorption. The enzyme's ability to catabolize elastin, collagen, and gelatin allow it to break down bone and cartilage. This catabolic activity is also partially responsible for the loss of lung elasticity and recoil in emphysema. Cathepsin K inhibitors, such as odanacatib, show great potential in the treatment of osteoporosis.

Cathepsin K expression is stimulated by inflammatory cytokines that are released after tissue injury.

Clinical significance

Cathepsin K is also expressed in a significant fraction of human breast cancers, where it could contribute to tumor invasiveness. Mutations in this gene are the cause of pycnodysostosis, an autosomal recessive disease characterized by osteosclerosis and short stature.

References

  1. ^ "Entrez Gene: CTSK cathepsin K". http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=1513. 
  2. ^ Inaoka T, Bilbe G, Ishibashi O, Tezuka K, Kumegawa M, Kokubo T (January 1995). "Molecular cloning of human cDNA for cathepsin K: novel cysteine proteinase predominantly expressed in bone". Biochem. Biophys. Res. Commun. 206 (1): 89–96. doi:10.1006/bbrc.1995.1013. PMID 7818555. 

Further reading

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