| In vitro kinase assays showed that RKIP antagonizes the activation of the IkappaB kinase ( IKK ) activity elicited by TNF alpha . ^^^ RKIP physically interacted with four kinases of the NF kappaB activation pathway , NF kappaB inducing kinase , transforming growth factor beta activated kinase 1 , IKKalpha , and IKKbeta . ^^^ |