Toll-like receptor signaling induces the expression of lympho-epithelial Kazal-type inhibitor in epidermal keratinocytes

Human kallikrein-related peptidases (KLKs) are secreted serine proteases encoded by 15 genes located on chromosome 19 [1], and KLK5 and KLK7 are known as major serine proteases in the epidermis. KLK5, a trypsin-like serine protease, cleaves the carboxyl side of arginine or lysine, and KLK7, a chymotrypsin-like serine protease, cleaves the carboxyl side of tyrosine or phenylalanine [2]. These proteases degrade corneodesmosome proteins (such as desmoglein 1, desmocollin 1, and corneodesmosin), leading to desquamation [3].