title: Binding of chondroitin 4-sulfate to cathepsin S regulates its enzymatic activity.
abstract: 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 ± 6 μM). 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 ± 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-C4-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.
authors: INSERM, UMR 1100, Pathologies Respiratoires: protéolyse et aérosolthérapie, Centre d'Etude des Pathologies Respiratoires, Université François Rabelais , F-37032 Tours cedex, France.
authors: Juliette
authors: J
authors: Sage
authors: Florian
authors: F
authors: Mallèvre
authors: Fabien
authors: F
authors: Barbarin-Costes
authors: Sergey A
authors: SA
authors: Samsonov
authors: Jan-Philip
authors: JP
authors: Gehrcke
authors: Maria Teresa
authors: MT
authors: Pisabarro
authors: Eric
authors: E
authors: Perrier
authors: Sylvianne
authors: S
authors: Schnebert
authors: André
authors: A
authors: Roget
authors: Thierry
authors: T
authors: Livache
authors: Carine
authors: C
authors: Nizard
authors: Gilles
authors: G
authors: Lalmanach
authors: Fabien
authors: F
authors: Lecaille
mesh_terms: D001665:Binding Sites; D002403:Cathepsins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002809:Chondroitin Sulfates / Q000378:metabolism*; D002850:Chromatography, Gel; D024141:Collagen Type IV / Q000378:metabolism; D003374:Coumarins / Q000378:metabolism; D004151:Dipeptides / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D062105:Molecular Docking Simulation; D056004:Molecular Dynamics Simulation; D020349:Surface Plasmon Resonance
chemical_list: D024141:Collagen Type IV; D003374:Coumarins; D004151:Dipeptides; C021159:benzyloxycarbonyl-phenylalanylarginine-4-methylcoumaryl-7-amide; D002809:Chondroitin Sulfates; D002403:Cathepsins; C028217:cathepsin S