Cysteine cathepsins: From structure, function and regulation to new frontiers

► Current advances in the field of cysteine cathepsins and their regulation. ► Cysteine cathepsin activity as a delicate balance of various factors. ► Structure of cysteine cathepsins and their mechanism of interaction with inhibitors. ► Inhibition of cysteine cathepsins by protein and small-molecule inhibitors. ► The increased expression of cysteine cathepsins implicated in various diseases.