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Clusterin is a specific stabilizer and liberator of extracellular cathepsin K
Author(s) -
Novinec Marko,
Lenarčič Brigita,
Baici Antonio
Publication year - 2012
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2012.03.004
Subject(s) - clusterin , extracellular , cathepsin a , chemistry , proteolysis , cathepsin , cathepsin s , cathepsin d , biochemistry , cathepsin l , cathepsin o , cathepsin b , cysteine , cathepsin e , enzyme , microbiology and biotechnology , biology , apoptosis
The cysteine peptidase cathepsin K is a major player in extracellular proteolysis. Here we describe the identification of the multifunctional extracellular chaperone clusterin as a cathepsin K‐binding protein. Clusterin increases the stability of cathepsin K in dilute solution and in the presence of high protein concentration. It does not alter the activity of the enzyme but acts as a liberator by preventing substrate inhibition. Kinetic measurements show that clusterin binds cathepsin K with high affinity ( K d = 0.5–0.6 nM). Altogether these results provide novel insights into the mechanisms involved in the fine‐tuning of cysteine cathepsin activity in the extracellular space.