What are Cathepsins?
Cathepsins are proteases, which degrade proteins, found in all animals and other organisms. There are about a dozen members of this family distinguished by their structure, catalytic mechanism, and which proteins they cleave.
When do most members become activated? They are activated at low pH found in lysosomes.
Where does Cathepsin activity take place? Almost entirely within lysosome organelles, except for cathepsin K, which operates extracellularly after osteoclast secretion in bone resorption (type of cellular turnover).
Why are Cathepsins important? They play vital roles in mammalian cellular turnover and degrade polypeptides. They are distinguished by their substrate specificities.
What are the three types of Cathepsins?
The three types of proteases are listed in the table below:
|Serine Protease||Cysteine protease||Aspartyl Protease|
Cathepsin L2 (or V)
Cathepsin Z (or X)
What are the clinical significances of these Cathepsins?
Some of the most recent ones are listed in the table below.
How were Cathepsins discovered?
A 1949 article from the Journal of Biological Chemistry has the earliest record of cathepsin research by Mary E. Maver and Antoinette E. Greco called The Hydrolysis of Nucleoproteins by Cathepsins from Calf Thymus. However, the references in the article show previous cathepsins were identified around the turn of the 20th century. Earlier work was completed by the laboratory of Max Bergmann, defining proteases in the first several decades of the century.
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Homo sapiens complex locus CTSB, encoding cathepsin B. (n.d.). Retrieved May 18, 2016, from http://www.ncbi.nlm.nih.gov/IEB/Research/Acembly/av.cgi?db=human
Hook, G., Yu, J., Kindy, M. S., & Hook, V. (2014). Cysteine Protease Inhibitor, E64D, Of Cathepsin B Reduces Pglu-Abeta And Abeta, And Improves Memory Deficits In The Applon Mouse Model Of Ad. Alzheimer's & Dementia, 10(4). doi:10.1016/j.jalz.2014.05.638