CTS gene family

Genes in the CTS gene family provide instructions for producing proteins called cathepsins. Cathepsins function as proteases, which means that they cut apart other proteins. Cathepsins are found in many types of cells and are typically located in lysosomes, compartments within cells that digest and recycle different types of molecules.

There are currently 23 known genes in the human CTS gene family. The genes in this family are designated by the letters CTS and an additional letter specific to that particular gene, for example CTSA and CTSL. The gene family includes multiple versions of CTSL; these genes are designated CTSL1, CTSL2, and CTSL3. Additionally, CTS genes that are similar to the CTSL genes have been named CTSLL (for CTSL-like) and are designated CTSLL1 through CTSLL7.

Cathepsins are involved in many different processes in cells and tissues. For example, they play roles in the self-destruction of cells (apoptosis), the formation of new blood vessels (angiogenesis), and cell growth and division (proliferation). Cathepsins are also involved in the normal functioning of the immune system and the breakdown and removal (resorption) of bone tissue that is no longer needed.

Changes in CTS genes have been associated with several complex diseases including rheumatoid arthritis, Alzheimer disease, and osteoporosis. Additionally, mutations in the CTSA gene cause a condition called galactosialidosis, which is characterized by skeletal malformations, an eye abnormality, and other health problems. Studies suggest that increased activity (expression) of cathepsins may also play a role in several types of cancer.