CTSB
Description
The CTSB (cathepsin B) is a protein-coding gene located on chromosome 8.
Cathepsin B is a lysosomal cysteine protease involved in intracellular proteolysis. It is encoded by the CTSB gene on chromosome 8p22, containing 13 exons. The gene's promoter is GC-rich and contains numerous SP1 sites, similar to housekeeping genes. Cathepsin B is upregulated in certain cancers, pre-malignant lesions, and other pathological conditions. The CTSB gene produces at least five transcript variants encoding the same protein. Cathepsin B is synthesized as a 339 amino acid preproenzyme with a 17 amino acid signal peptide. After transport to the Golgi apparatus, the 43/46 kDa procathepsin B matures into a two-chain protein composed of a 25-26 kDa heavy chain and a 5 kDa light chain linked by a disulfide bond dimer. Cathepsin B can enhance the activity of other proteases, including matrix metalloproteinase, urokinase, and cathepsin D. This function is critical for proteolysis of extracellular matrix components, disruption of intercellular communication, and reduced protease inhibitor expression.
CTSB is also known as APPS, CPSB, KWE, RECEUP.
