Sylviane Komesli, Martine Page, and Patrick Dutartre
Dpartement dImmunologie, Laboratoires Fournier S.A., France
TGF- type I and type II receptors form ligand dependent heteromeric signaling complexes, in which transforming growth factor- receptor type II (TRII) tends to act as the primary receptor. In the present study, we investigated the feasibility of using the FlashPlate platform to assay a chimeric soluble type II receptor fused with the Fc regions of human immunoglobulin (TRIIs-Fc), in order to screen for potent agonists and antagonists of TGF.
Transforming growth factors 1, 2 and 3 (TGF-s) are multifunctional cytokines involved in the regulation of cell proliferation, differentiation and extracellular matrix production. In mammalian cells, responses to TGF- are mediated by types I and II cell surface receptors (TRI and TRII respectively) which are expressed in most cell types and tissues. TGF- binds directly to TRII, allowing this receptor to associate with and phosphorylate TRI, which then propagates the signal through activation of Smad2 and Smad4 heteromeric complexes1.
At this time, there are no known, clinically useful TGF- agonists or antagonists. A better understanding of the mechanism of activation of the TGF- receptor complexes may be useful, therefore, as a step towards the development of TGF- antagonist or agonist drugs. We have investigated the possibility of using the soluble extracellular domain of TRII in a nonseparation microplate receptor binding assay.
To facilitate this approach and increase the probability of success, we constructed a chimeric soluble receptor, by fusing the extracellular domain of TRII to the Fc regions of human immunoglobulin (TRIIs-Fc). Through the Fc region, the chimeric receptor, TRIIs-Fc, expressed in a transiently tran