passages.id: split_6_test_1305_passage
passages.type: progene_text
passages.text: This report suggests that the cAMP / protein kinase A ( PKA ) component of the IL-4 receptor signalling programme in human tonsillar B cells has a functionally important role in regulating expression of the CD25 gene by attenuating activity of a protein binding to a potent negative regulatory element ( NRE ) in the CD25 promoter ; this effect can be mimicked by agents that elevate cAMP and blocked by inhibitors of PKA but not protein kinase C ( PKC ) .