Biologically active fibroblast growth factor 1 tagged with various epitopes

BACKGROUND: Fibroblast growth factor (FGF) family members are involved in the regulation of a variety of biological phenomena. Because most of their activity is exerted via a signaling complex composed of FGF, heparin/heparan sulfate and FGF receptor tyrosine kinase, it is important to study the dynamic behavior of all the molecules in the complex without disturbing their interaction or activity. FINDINGS: We used E. coli to express biologically active human FGF1 tagged at its C-terminus with myc-(His)(6), V5-(His)(6 )or 3xFLAG-(His)(6). We found that the tagged FGF1s had affinities for heparin that were similar to that of the native form. The tagged FGF1s also exhibited mitogenic activity similar to that of the native form. Apparently, the tags do not interfere with the formation of the three-member complex involving FGF1, FGF receptor and heparan sulfate/heparin. CONCLUSION: Tagged FGF1s should be useful for investigating the dynamic behavior of FGF1 in the context of its three-member signaling complex and other molecular complexes.