| Herein , we show that Bcl 3 stimulates the activating protein 1 ( AP 1 ) transactivation , either alone or in conjunction with transcription integrators steroid receptor coactivator 1 and CREB binding protein / p300 . ^^^ The C terminal 158 residues of Bcl 3 exhibited an autonomous transactivation function and interacted with specific subregions of the AP 1 components c Jun and c Fos , CREB binding protein / p300 , and steroid receptor coactivator 1 , as demonstrated by the yeast and mammalian two hybrid tests as well as glutathione S transferase pull down assays . ^^^ |