title: Cathepsin B activity regulation. Heparin-like glycosaminogylcans protect human cathepsin B from alkaline pH-induced inactivation.
abstract: It has been shown that lysosomal cysteine proteinases, specially cathepsin B, has been implicated in a variety of diseases involving tissue remodeling states, such as inflammation, parasite infection, and tumor metastasis, by degradation of extracellular matrix components. Recently, we have shown that heparin and heparan sulfate bind to papain specifically; this interaction induces an increase of its alpha-helix content and stabilizes the enzyme structure even at alkaline pH (Almeida, P. C., Nantes, I. L., Rizzi, C. C. A., Júdice, W. A. S., Chagas, J. R., Juliano, L., Nader, H. B., and Tersariol, I. L. S. (1999) J. Biol. Chem. 274, 30433-30438). In the present work, a combination of circular dichroism analysis, affinity chromatography, cathepsin B mutants, and fluorogenic substrate assays were used to characterize the interaction of human cathepsin B with glycosaminoglycans. The nature of the cathepsin B-glycosaminoglycans interaction was sensitive to the charge and type of polysaccharide. Like papain, heparin and heparan sulfate bind cathepsin B specifically, and this interaction reduces the loss of cathepsin B alpha-helix content at alkaline pH. Our data show that the coupling of cathepsin B with heparin or heparan sulfate can potentiate the endopeptidase activity of the cathepsin B, increasing 5-fold the half-life (t(12)) of the enzyme at alkaline pH. Most of these effects are related to the interaction of heparin and heparan sulfate with His(111) residue of the cathepsin B occluding loop. These results strongly suggest that heparan sulfate may be an important binding site for cathepsin B at cell surface, reporting a novel physiological role for heparan sulfate proteoglycans.
authors.affiliation: Centro Interdisciplinar de Investigação Bioquimica, Universidade de Mogi das Cruzes, Prédio I, Centro de Ciências Tecnológicas, sala 1S-15, Av. Dr. Candido X. de Almeida Souza 200, CEP 08780-911, Mogi das Cruzes, SP, Brazil.
authors.forename: P C
authors.initials: PC
authors.lastname: Almeida
authors.forename: I L
authors.initials: IL
authors.lastname: Nantes
authors.forename: J R
authors.initials: JR
authors.lastname: Chagas
authors.forename: C C
authors.initials: CC
authors.lastname: Rizzi
authors.forename: A
authors.initials: A
authors.lastname: Faljoni-Alario
authors.forename: E
authors.initials: E
authors.lastname: Carmona
authors.forename: L
authors.initials: L
authors.lastname: Juliano
authors.forename: H B
authors.initials: HB
authors.lastname: Nader
authors.forename: I L
authors.initials: IL
authors.lastname: Tersariol
mesh_terms: D019943:Amino Acid Substitution; D002401:Cathepsin B / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D002809:Chondroitin Sulfates / Q000378:metabolism / Q000494:pharmacology; D002846:Chromatography, Affinity; D002942:Circular Dichroism; D003001:Cloning, Molecular; D003871:Dermatan Sulfate / Q000378:metabolism / Q000494:pharmacology; D016264:Dextran Sulfate / Q000378:metabolism / Q000494:pharmacology; D004795:Enzyme Stability; D006025:Glycosaminoglycans / Q000378:metabolism* / Q000494:pharmacology; D006493:Heparin / Q000378:metabolism* / Q000494:pharmacology; D006497:Heparan Sulfate / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D011489:Protein Denaturation / Q000187:drug effects; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D002401:Cathepsin B; D002809:Chondroitin Sulfates; D003871:Dermatan Sulfate; D016264:Dextran Sulfate; D006025:Glycosaminoglycans; D006493:Heparin; D006497:Heparan Sulfate; D011994:Recombinant Proteins