Expression of recombinant extracellular domain of the type II transforming growth factor-beta receptor: utilization in a modified enzyme-linked immunoabsorbent assay to screen TGF-beta agonists and antagonists

TGF-beta is a ubiquitous protein that exhibits a broad spectrum of biological activity. The prokaryotic expression and purification of the extracellular domain of the type II TGF-beta receptor (T beta R-II-ED), without the need for fusion protein cleavage and refolding, is described. The recombinant T beta R-II-ED fusion protein bound commercially available TGF-beta 1 and displayed an affinity of 11.1 nM. In a modified ELISA, receptor binding to TGF-beta1 was inhibited by TGF-beta 3. The technique lends itself to high-throughput screening of combinatorial libraries for the identification of TGF-beta agonists and antagonists and this, in turn, may have important therapeutic implications.