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Kallikrein-related Peptidase-8 (KLK8) Is an Active Serine Protease in Human Epidermis and Sweat and Is Involved in a Skin Barrier Proteolytic Cascade
被引:75
作者:
Eissa, Azza
[2
]
Amodeo, Vanessa
Smith, Christopher R.
[3
]
Diamandis, Eleftherios P.
[1
,2
,3
]
机构:
[1] Mt Sinai Hosp, Joseph & Wolf Lebov Ctr, Dept Pathol & Lab Med, Toronto, ON M5T 3L9, Canada
[2] Univ Toronto, Dept Lab Med & Pathobiol, Toronto, ON M5S 1A8, Canada
[3] Univ Hlth Network, Dept Clin Biochem, Toronto, ON M5G 1X5, Canada
关键词:
HUMAN TISSUE KALLIKREINS;
HUMAN STRATUM-CORNEUM;
NEUROPSIN MESSENGER-RNA;
NETHERTON-SYNDROME;
TRYPSIN-LIKE;
ENZYMATIC CHARACTERIZATION;
MOLECULAR-CLONING;
SEMINAL PLASMA;
GENE FAMILY;
EXPRESSION;
D O I:
10.1074/jbc.M110.125310
中图分类号:
Q5 [生物化学];
Q7 [分子生物学];
学科分类号:
071010 ;
081704 ;
摘要:
Kallikrein-related peptidase-8 (KLK8) is a relatively uncharacterized epidermal protease. Although proposed to regulate skin-barrier desquamation and recovery, the catalytic activity of KLK8 was never demonstrated in human epidermis, and its regulators and targets remain unknown. Herein, we elucidated for the first time KLK8 activity in human non-palmoplantar stratum corneum and sweat ex vivo. The majority of stratum corneum and sweat KLK8 was catalytically active, displaying optimal activity at pH 8.5 and considerable activity at pH 5. We also showed that KLK8 is a keratinocyte-specific protease, not secreted by human melanocytes or dermal fibroblasts. KLK8 secretion increased significantly upon calcium induction of terminal keratinocyte differentiation, suggesting an active role for this protease in upper epidermis. Potential activators, regulators, and targets of KLK8 activity were identified by in vitro kinetic assays using pro-KLK8 and mature KLK8 recombinant proteins produced in Pichia pastoris. Mature KLK8 activity was enhanced by calcium and magnesium ions and attenuated by zinc ions and by autocleavage after Arg(164). Upon screening KLK8 cleavage of a library of FRET-quenched peptides, trypsin-like specificity was observed with the highest preference for (R/K)(S/T)(A/V) at P1-P1'-P2'. We also demonstrated that KLK5 and lysyl endopeptidase activate latent pro-KLK8, whereas active KLK8 targets pro-KLK11, pro-KLK1, and LL-37 antimicrobial peptide activation in vitro. Together, our data identify KLK8 as a new active serine protease in human stratum corneum and sweat, and we propose regulators and targets that augment its involvement in a skin barrier proteolytic cascade. The implications of KLK8 elevation and hyperactivity in desquamatory and inflammatory skin disease conditions remain to be studied.
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页码:687 / 706
页数:20
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