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Complex regulation of the transactivation function of hypoxia-inducible factor-1 alpha by direct interaction with two distinct domains of the CREB-binding protein/p300.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2010 Jan 22; Vol. 285 (4), pp. 2601-9. Date of Electronic Publication: 2009 Oct 30. - Publication Year :
- 2010
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Abstract
- Activation of transcription in response to low oxygen tension is mediated by the hypoxia-inducible factor-1 (HIF-1). HIF-1 is a heterodimer of two proteins: aryl hydrocarbon receptor nuclear translocator and the oxygen-regulated HIF-1 alpha. The C-terminal activation domain of HIF-1 alpha has been shown to interact with cysteine/histidine-rich region 1 (CH1) of the coactivator CBP/p300 in a hypoxia-dependent manner. However, HIF forms lacking C-terminal activation domain (naturally occurring or genetically engineered) are still able to activate transcription of target genes in hypoxia. Here, we demonstrate that the N-terminal activation domain (N-TAD) of HIF-1 alpha interacts with endogenous CBP and that this interaction facilitates its transactivation function. Our results show that interaction of HIF-1 alpha N-TAD with CBP/p300 is mediated by the CH3 region of CBP known to interact with, among other factors, p53. Using fluorescence resonance energy transfer experiments, we demonstrate that N-TAD interacts with CH3 in vivo. Coimmunoprecipitation assays using endogenous proteins showed that immunoprecipitation of CBP in hypoxia results in the recovery of a larger fraction of HIF-1 alpha than of p53. Chromatin immunoprecipitation demonstrated that at 1% O(2) CBP is recruited to a HIF-1 alpha but not to a p53 target gene. Upon activation of both pathways, lower levels of chromatin-associated CBP were detected at either target gene promoter. These results identify CBP as the coactivator directly interacting with HIF-1 alpha N-TAD and mediating the transactivation function of this domain. Thus, we suggest that in hypoxia HIF-1 alpha is a major CBP-interacting transcription factor that may compete with other CBP-dependent factors, including p53, for limiting amounts of this coactivator, underscoring the complexity in the regulation of gene expression by HIF-1 alpha.
- Subjects :
- 2,2'-Dipyridyl pharmacology
Cell Line
Chelating Agents pharmacology
Cysteine metabolism
E1A-Associated p300 Protein chemistry
HeLa Cells
Histidine metabolism
Humans
Hypoxia metabolism
Kidney cytology
Mutagenesis
Protein Interaction Domains and Motifs drug effects
Protein Interaction Domains and Motifs physiology
Protein Structure, Tertiary
Transcriptional Activation physiology
Tumor Suppressor Protein p53 metabolism
p300-CBP Transcription Factors chemistry
E1A-Associated p300 Protein metabolism
Hypoxia physiopathology
Hypoxia-Inducible Factor 1, alpha Subunit chemistry
Hypoxia-Inducible Factor 1, alpha Subunit genetics
Hypoxia-Inducible Factor 1, alpha Subunit metabolism
p300-CBP Transcription Factors metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1083-351X
- Volume :
- 285
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 19880525
- Full Text :
- https://doi.org/10.1074/jbc.M109.021824