passages.id: split_8_test_3058_passage
passages.type: progene_text
passages.text: Our results support a cooperative model of binding for the inhibin receptor ( ActRII . sTbetaRIII complex ) but not for activin receptors ( type II + type I ) and demonstrate that a complex composed of activin type II receptors and TbetaRIII is both necessary and sufficient for high affinity inhibin binding .