MAP kinase-dependent transcriptional coactivation by Elk-1 and its cofactor CBP.
A plethora of signals induce the c-fos proto-oncogene via phosphorylation of the transcription factor Elk-1 by MAP kinase. We show that the coactivator CBP cooperates with Elk-1 to stimulate c-fos. Elk-1 physically interacts with CBP, which is dependent on the transactivation domain of Elk-1 but is independent of MAP kinase phosphorylation. However, functional cooperation between Elk-1 and CBP requires phosphorylation of Elk-1. Importantly, a carboxy-terminal transactivation domain of CBP itself is phosphorylated by MAP kinase, whereby the transactivation potential of CBP is enhanced. Thus, MAP kinase may not solely activate specific transcription factors but also the coactivator CBP, identifying a novel aspect of MAP kinase function. Thereby MAP kinase stimulation can pleiotropically affect activation of genes regulated by different transcription factors interacting with the same coactivator CBP.
Janknecht
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R
Institute for Molecular Biology, Hannover Medical School, Germany.
Nordheim
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A
D000818:Animals; D050882:CREB-Binding Protein; D002460:Cell Line; D004268:DNA-Binding Proteins; D008156:Luciferases / Q000235:genetics; D009687:Nuclear Proteins / Q000378:metabolism*; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D011817:Rabbits; D015534:Trans-Activators; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation; D050807:ets-Domain Protein Elk-1
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D050807:ets-Domain Protein Elk-1; D008156:Luciferases; D050882:CREB-Binding Protein; D011494:Protein Kinases