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TSG-6 binds via its CUB_C domain to the cell-binding domain of fibronectin and increases fibronectin matrix assembly

2007; Elsevier BV; Volume: 27; Issue: 3 Linguagem: Inglês

10.1016/j.matbio.2007.10.003

1569-1802

Светлана А. Кузнецова, David Mahoney, Gema Martin‐Manso, Tariq Ali, Hilke A. Nentwich, John M. Sipes, Bai Jin Zeng, Tikva Vogel, Anthony J. Day, David D. Roberts,

Cellular Mechanics and Interactions

Human plasma fibronectin binds with high affinity to the inflammation-induced secreted protein TSG-6. Fibronectin binds to the CUB_C domain of TSG-6 but not to its Link module. TSG-6 can thus act as a bridging molecule to facilitate fibronectin association with the TSG-6 Link module ligand thrombospondin-1. Fibronectin binding to TSG-6 is divalent cation-independent and is conserved in cellular fibronectins. Based on competition binding studies using recombinant and proteolytic fragments of fibronectin, TSG-6 binding localizes to type III repeats 9–14 of fibronectin. This region of fibronectin contains the Arg-Gly-Asp sequence recognized by α5β1 integrin, but deletion of that sequence does not prevent TSG-6 binding, and TSG-6 does not inhibit cell adhesion on fibronectin substrates mediated by this integrin. This region of fibronectin is also involved in fibronectin matrix assembly, and addition of TSG-6 enhances exogenous and endogenous fibronectin matrix assembly by human fibroblasts. Therefore, TSG-6 is a high affinity ligand that can mediate fibronectin interactions with other matrix components and modulate some interactions of fibronectin with cells.