Cystatin SA

Cystatin-2 (CST2) is also known as Cystatin-SA, Cystatin-S5, is a secreted thiol protease inhibitor, which belongs to the cystatin family. The type 2 cystatin proteins are a class of cysteine proteinase inhibitors found in a variety of human fluids and secretions, where they appear to provide protective functions. The CST1, CST2, CST4, and CST5 are expressed in differential, tissue-specific patterns. CST2 is expressed in submandibular and sublingual saliva but not in parotid saliva (at protein level) and is also expressed in submandibular gland and parotid gland.