passages.id: split_1_test_2798_passage
passages.type: progene_text
passages.text: Analyses of mutant I1A cells , which lack the IL-1 receptor - associated kinase ( IRAK ) , and of I1A cells reconstituted with deletion mutants of IRAK show that the IL-1 - mediated phosphorylation of Stat1 on serine requires the IRAK protein but not its kinase activity and does not involve phosphatidylinositol-3'-kinase ( PI3K ) or the mitogen - activated protein ( MAP ) kinases p38 or ERK .