Determination of interactions between human thrombopoietin and its receptor MPL by yeast two-hybrid system and affinity biosensor

The binding of human thrombopoietin to the extracellular domain of its rece ptor MPL prompts a cascade transduction of intracellular signals, leading t o the development of megakaryocyte precursors and the production of circula ting platelets. We have used a yeast two-hybrid system to reveal, via in vi vo interactions between different deletion constructs of MPL and thrombopoi etin, that the extracellular subunit 1 of MPL is the ligand binding site an d the N-terminal domain of thrombopoietin alone is sufficient for the bindi ng. The extracellular portion of MPL was heterologously expressed in E. col i and its specific affinity with thrombopoietin was visualized in vitro by resonance mirror biosensor technique. (C) 2000 Published by Elsevier Scienc e Ltd. All rights reserved.