Transcriptional activation by STAT6 requires the direct interaction with NCoA-1.
Signal transducer and activator of transcription 6 (STAT6) is a transcription factor that is activated by interleukin-4 (IL-4)-induced tyrosine phosphorylation and mediates most of the IL-4-induced gene expression. Transcriptional activation by STAT6 requires the interaction with coactivators like p300 and the CREB-binding protein (CBP). In this study we have investigated ... the function of the CBP-associated members of the p160/steroid receptor coactivator family in the transcriptional activation by STAT6. We found that only one of them, NCoA-1, acts as a coactivator for STAT6 and interacts directly with the transactivation domain of STAT6. The N-terminal part of NCoA-1 interacts with the far C-terminal part of the STAT6 transactivation domain but does not interact with the other members of the STAT family. This domain of NCoA-1 has a strong inhibitory effect on STAT6-mediated transactivation when overexpressed in cells, illustrating the importance of NCoA-1 for STAT6-mediated transactivation. In addition, we showed that both coactivators CBP and NCoA-1 bind independently to specific regions within the STAT6 transactivation domain. Our results suggest that multiple contacts between NCoA-1, CBP, and STAT6 are required for transcriptional activation. These findings provide new mechanistic insights into how STAT6 can recruit coactivators required for IL-4-dependent transactivation.
Mesh Terms:
Amino Acids, Cell Line, Histone Acetyltransferases, Humans, Interleukin-4, Nuclear Receptor Coactivator 1, Protein Binding, Receptors, Retinoic Acid, STAT6 Transcription Factor, Trans-Activators, Transcription Factors, Transcriptional Activation
Amino Acids, Cell Line, Histone Acetyltransferases, Humans, Interleukin-4, Nuclear Receptor Coactivator 1, Protein Binding, Receptors, Retinoic Acid, STAT6 Transcription Factor, Trans-Activators, Transcription Factors, Transcriptional Activation
J. Biol. Chem.
Date: Dec. 07, 2001
PubMed ID: 11574547
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