Large scale protein production of the extracellular domain of the transforming growth factor-β type II receptor using the Pichia pastoris expression system

To study the (patho)physiological role of transforming growth factor-β (TGF-β), potent and selective inhibitors are necessary. Since TGF-β signaling is initiated by the high affinity binding to the type II receptor (RII), the extracellular part of RII (solRII) can function as a TGF-β antagonist. SolRII was cloned and large-scale protein synthesis was performed in the yeast Pichia pastoris expression system. Our results indicate that via this system, high levels of pure concentrated solRII can be obtained. Moreover, purified solRII is an active protein as shown by ELISA and bioassay. In conclusion, our large-scale protein expression procedure results in high quantities of purified solRII, which is a powerful tool to study the natural role of TGF-β.