p300/cAMP-responsive element-binding protein interactions with Ets-1 and Ets-2 in the transcriptional activation of the human stromelysin promoter

In this paper we show that transcription factors Ets-1 and Ets-2 recruit tr anscription adapter proteins p300 and CBP (cAMP-responsive element-binding protein) during the transcriptional activation of the human stromelysin pro moter, which contains palindromic Ets-binding sites. Ets-2 and p300/CBP exi st as a complex in vivo. Two regions of p300/CBP between amino acids (a.a.) 328 and 596 and a.a. 1678 and 2370 independently can interact with Ets-1 a nd Ets-2 in vitro and in vivo. Both these regions of p300/CBP bind to the t ransactivation domain of Ets-2, whereas the C-terminal region binds only to the DNA binding domain of Ets-2. The N- and the C-terminal regions of CBP (a.a. 1-1097 and 1678-2442, respectively) which lack histone acetylation ac tivity independently are capable of coactivating Ets-2. Other Ets family tr anscription factors failed to cooperate with p300/CBP in stimulating the st romelysin promoter. The LXXLL sequence, reported to be important in recepto r-coactivator interactions, does not appear to play a role in the interacti on of Ets-2 with p300/CBP. Previous studies have shown that the stimulation of transcriptional activation activity of Ets-2 requires phosphorylation o f threonine 72 by the Ras/mitogen-activated protein kinase signaling pathwa y. We show that mutation of this site does not affect its capacity to bind to and to cooperate with p300/CBP.