Cathepsin L is responsible for processing and activation of proheparanase through multiple cleavages of a linker segment
| Autor: | Carmela Palermo, Bedrick B. Gadea, Johanna A. Joyce, Israel Vlodavsky, Tamar Peretz, Ghada Abboud-Jarrous, Ruth Atzmon |
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| Rok vydání: | 2008 |
| Předmět: |
Protein subunit
Cathepsin L Molecular Sequence Data Glycobiology and Extracellular Matrices Biochemistry Gene Expression Regulation Enzymologic Mass Spectrometry Cathepsin O Cell Line Tumor Humans Heparanase Amino Acid Sequence Gene Silencing RNA Small Interfering Molecular Biology Peptide sequence Cathepsin S Glucuronidase Cathepsin Binding Sites biology Sequence Homology Amino Acid Cell Biology Fibroblasts Cathepsins Cell biology Protein Structure Tertiary Cysteine Endopeptidases biology.protein Linker Protein Binding |
| Zdroj: | The Journal of biological chemistry. 283(26) |
| ISSN: | 0021-9258 |
| Popis: | Heparanase is an endo-β-d-glucuronidase that degrades heparan sulfate in the extracellular matrix and on the cell surface. Human proheparanase is produced as a latent protein of 543 amino acids whose activation involves excision of an internal linker segment (Ser110–Gln157), yielding the active heterodimer composed of 8- and 50-kDa subunits. Applying cathepsin L knock-out tissues and cultured fibroblasts, as well as cathepsin L gene silencing and overexpression strategies, we demonstrate, for the first time, that removal of the linker peptide and conversion of proheparanase into its active 8 + 50-kDa form is brought about predominantly by cathepsin L. Excision of a 10-amino acid peptide located at the C terminus of the linker segment between two functional cathepsin L cleavage sites (Y156Q and Y146Q) was critical for activation of proheparanase. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry demonstrates that the entire linker segment is susceptible to multiple endocleavages by cathepsin L, generating small peptides. Mass spectrometry demonstrated further that an active 8-kDa subunit can be generated by several alternative adjacent endocleavages, yielding the precise 8-kDa subunit and/or slightly elongated forms. Altogether, the mode of action presented here demonstrates that processing and activation of proheparanase can be brought about solely by cathepsin L. The critical involvement of cathepsin L in proheparanase processing and activation offers new strategies for inhibiting the prometastatic, proangiogenic, and proinflammatory activities of heparanase. |
| Databáze: | OpenAIRE |
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