Different regions of the class P-III snake venom metalloproteinase jararhagin are involved in binding to α₂β₁ integrin and collagen

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• 作者：Isabelle Tanjoni ; Karla Evangelista ; Maisa S. Della-Casa ; Diego Butera ; Geraldo S. Magalhã ; es ; Cristiani Baldo ; Patrí ; cia B. Clissa ; Irene Fern ; es ; Johannes Eble ; Ana M. Moura-da-Silva
• 关键词：Snake venoms ; Metalloproteinase ; Jararhagin ; Collagen ; Integrin ; Antibodies
• 刊名：Toxicon
• 出版年：2010
• 出版时间：1 June 2010
• 年：2010
• 卷：55
• 期：6
• 页码：1093-1099
• 全文大小：381 K

文摘

SVMPs are multi-domain proteolytic enzymes in which disintegrin-like and cysteine-rich domains bind to cell receptors, plasma or ECM proteins. We have recently reported that jararhagin, a P-III class SVMP, binds to collagen with high affinity through an epitope located within the Da-disintegrin sub-domain. In this study, we evaluated the binding of jararhagin to α₂β₁ integrin (collagen receptor) using monoclonal antibodies and recombinant jararhagin fragments. In solid phase assays, binding of jararhagin to α₂β₁ integrin was detectable from concentrations of 20 nM. Using recombinant fragments of jararhagin, only fragment JC76 (residues 344–421), showed a significant binding to recombinant α₂β₁ integrin. The anti-jararhagin monoclonal antibody MAJar 3 efficiently neutralised binding of jararhagin to collagen, but not to recombinant α₂β₁ integrin nor to cell-surface-exposed α₂β₁ integrin (α₂-K562 transfected cells and platelets). The same antibody neutralised collagen-induced platelet aggregation. Our data suggest that jararhagin binding to collagen and α₂β₁ integrin occurs by two independent motifs, which are located on disintegrin-like and cysteine-rich domains, respectively. Moreover, toxin binding to collagen appears to be sufficient to inhibit collagen-induced platelet aggregation.