Binding of Chondroitin 4-Sulfate to Cathepsin S Regulates Its Enzymatic Activity
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- 作者：Juliette Sage ; Florian Mall猫vre ; Fabien Barbarin-Costes ; Sergey A. Samsonov ; Jan-Philip Gehrcke ; Maria Teresa Pisabarro ; Eric Perrier ; Sylvianne Schnebert ; Andr茅 Roget ; Thierry Livache ; Carine Nizard ; Gilles Lalmanach ; Fabien Lecaille
- 刊名：Biochemistry
- 出版年：2013
- 出版时间：September 17, 2013
- 年：2013
- 卷：52
- 期：37
- 页码：6487-6498
- 全文大小：477K
- 年卷期：v.52,no.37(September 17, 2013)
- ISSN：1520-4995
文摘
Human cysteine cathepsin S (catS) participates in distinct physiological and pathophysiological cellular processes and is considered as a valuable therapeutic target in autoimmune diseases, cancer, atherosclerosis, and asthma. We evaluated the capacity of negatively charged glycosaminoglycans (heparin, heparan sulfate, chondroitin 4/6-sulfates, dermatan sulfate, and hyaluronic acid) to modulate the activity of catS. Chondroitin 4-sulfate (C4-S) impaired the collagenolytic activity (type IV collagen) and inhibited the peptidase activity (Z-Phe-Arg-AMC) of catS at pH 5.5, obeying a mixed-type mechanism (estimated Ki = 16.5 卤 6 渭M). Addition of NaCl restored catS activity, supporting the idea that electrostatic interactions are primarly involved. Furthermore, C4-S delayed in a dose-dependent manner the maturation of procatS at pH 4.0 by interfering with the intermolecular processing pathway. Binding of C4-S to catS was demonstrated by gel-filtration chromatography, and its affinity was measured by surface plasmon resonance (equilibrium dissociation constant Kd = 210 卤 40 nM). Moreover, C4-S induced subtle conformational changes in mature catS as observed by intrinsic fluorescence spectroscopy analysis. Molecular docking predicted three specific binding sites on catS for C4-S that are different from those found in the crystal structure of the cathepsin K鈥揅4-S complex. Overall, these results describe a novel glycosaminoglycan-mediated mechanism of catS inhibition and suggest that C4-S may modulate the collagenase activity of catS in vivo.