Cathepsins refer to a group of lysosomal proteases that play a crucial role in protein degradation and turnover within cells. These enzymes are primarily found within the lysosomes, which are membrane-bound organelles responsible for breaking down cellular waste and cellular components.
Cathepsins are known for their ability to cleave peptide bonds and break down various proteins, including extracellular matrix proteins, receptor proteins, and cytoskeletal proteins. They are able to degrade both endogenous proteins, as well as exogenous proteins taken up by the cell through endocytosis.
There are several different types of cathepsins, classified by their distinct molecular structures and specific functions. Examples include cathepsin D, cathepsin B, cathepsin K, and cathepsin L.
These enzymes play a critical role in various physiological processes, including cell death, tissue remodeling, and antigen processing. They are involved in crucial cellular functions such as maintaining cellular homeostasis and regulating immune responses.
Abnormalities in cathepsin activity have been linked to various pathological conditions, including cancer, neurodegenerative diseases, and autoimmune disorders. Studies have shown that cathepsins can promote tumorigenesis by facilitating tissue invasion, metastasis, and angiogenesis.
In summary, cathepsins are a group of lysosomal proteases responsible for protein degradation and turnover within cells. They are involved in numerous physiological processes and have been implicated in the development and progression of various diseases.
