Cathepsin K
Cathepsin K (CTSK) is a lysosomal cysteine proteinase of the peptidase C1 family that drives osteoclastic bone resorption and remodelling. It is also known as PKND, CTSO, CTSO2 and PYCD, and its gene is mutated in pycnodysostosis. Browse Assay Genie's current range of Cathepsin K research reagents below, or read on for the biology behind the target.
Cathepsin K is a thiol protease involved in osteoclastic bone resorption, and it may participate in disorders of bone remodelling. It shows potent endoprotease activity against fibrinogen at acid pH and may play an important role in extracellular matrix degradation. In the thyroid follicle lumen, it contributes to the release of the hormone thyroxine (T4) by limited proteolysis of thyroglobulin (TG).
The CTSK gene encodes a lysosomal cysteine proteinase that belongs to the peptidase C1 family. The enzyme is classed as EC 3.4.22.38 and sits within the HGNC gene groups for cathepsins, elastases and cysteine endopeptidases. UniProt records it in the lysosome, in the secreted fraction and at the apical cell membrane. The protein is predominantly expressed in osteoclasts, and mouse and rat each carry a Ctsk ortholog, which supports comparative work in rodent models.
Cathepsin K is not confined to bone. NCBI Gene notes that it is also expressed in a significant fraction of human breast cancers, where it could contribute to tumour invasiveness. Mutations in the gene cause pycnodysostosis, an autosomal recessive disease characterised by osteosclerosis and short stature. This is the origin of the previous gene name, cathepsin K (pycnodysostosis), and of the alias PKND. Researchers studying the CTSK gene, the cathepsin K protein or its activity in bone, thyroid and tumour biology will find this target relevant.
Cathepsin K is a lysosomal protease involved in osteoclastic bone resorption and may participate in disorders of bone remodelling.
The enzyme may play an important role in extracellular matrix degradation and is a potent endoprotease against fibrinogen at acid pH.
Cathepsin K releases thyroxine (T4) through limited proteolysis of thyroglobulin in the thyroid follicle lumen.
Cathepsin K is expressed in a significant fraction of human breast cancers, where it could contribute to tumour invasiveness.
Cathepsin K is a thiol protease involved in osteoclastic bone resorption. It may help degrade extracellular matrix, shows potent endoprotease activity against fibrinogen at acid pH, and releases thyroxine (T4) by limited proteolysis of thyroglobulin in the thyroid follicle lumen.
Cathepsin K is encoded by CTSK. Aliases and previous symbols include PKND, CTSO2, CTSO and PYCD. The previous HGNC name was cathepsin K (pycnodysostosis), which reflects the disease caused by mutations in the gene.
Mutations in CTSK cause pycnodysostosis, an autosomal recessive disease with osteosclerosis and short stature. It is also expressed in many human breast cancers. Mouse and rat both have a Ctsk ortholog; check the datasheet of any product for its validated reactivity.
Other cathepsins, protease substrates and bone remodelling targets with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P43235; product specifications from Assay Genie datasheets.