Cystatin-SA (CST2)

Cystatin-SA (CST2) is a secreted member of the type 2 cystatin family of cysteine protease inhibitors, found abundantly in human saliva, tears, and seminal plasma[1][2][3][5]. It plays an important role in inhibiting thiol (cysteine) proteases, thereby contributing to tissue protection and homeostasis in secretory fluids. While CST2 is not considered a classical drug target or receptor, altered expression has been implicated in modulating cell growth and drug sensitivity in certain cancers, such as increased sensitivity of gastric cancer cells to oxaliplatin via the PI3K/AKT pathway[6]. There are currently no known pharmaceuticals that directly target CST2, and its principal biological function remains natural protease inhibition in extracellular environments.

Other names

Cystatin-SACST2Cystatin-2Cystatin-S5cystatin 2cystatin S5cysteine-proteinase inhibitorsalivary cysteine (thiol) protease inhibitor[1][2][3][5]