passages.id: split_1_test_2636_passage
passages.type: progene_text
passages.text: Using two independent approaches , one involving inhibition of specific signaling molecules and the other employing cell lines that express particular EpoR mutants and thereby activate only subsets of signaling cascades , we demonstrate that induction of SOCS1 , SOCS2 , SOCS3 , and cytokine - inducible SH2 - containing protein ( CIS ) in response to EPO stimulation appears to depend on Stat5 but not on mitogen - activated protein kinase ( MAPK ) or phosphatidylinositol 3-kinase ( PI3K ) .