Structural basis for recruitment of CBP/p300 by hypoxia-inducible factor-1α

Freedman, Steven J.; Sun, Zhenyu; Poy, Florence; Kung, Andrew L.; Livingston, David M.; Wagner, Gerhard; Eck, Michael J.

doi:10.1073/pnas.082117899

Cited by 417 publications

(478 citation statements)

References 42 publications

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confidence: 93%

“…Notably, this interaction was abolished when EDTA was included in the binding reaction. These results are consistent with previous reports showing that the structural integrity of C/H1, and its ability to interact with HIF1α, is dependent upon proper folding in the presence of Zn 2+ [2,4].Of greater significance is the observation by Matt et al[5] that HDM2, the human homologue of the well-characterized C/ H1-binding partner MDM2 (mouse double minute protein), does not bind to native C/H1. Instead, HDM2 was found to nonspecifically interact with the unstructured form of C/H1 present under EDTA-induced denaturing conditions.…”

supporting

confidence: 92%

“…Prominent among these are cysteine/ histidine-rich regions 1 and 3 (C/H1 and C/H3), each of which contains cysteine/histidine-rich sequences that co-ordinate three Zn 2+ atoms. These well-characterized domains form Zn 2+ -dependent helical fold structures that stabilize intermolecular interactions and mediate the recruitment of CBP/p300 to promoterbound transcription factors [2][3][4]. A third zinc-binding region of CBP/p300, called C/H2, comprises a highly conserved PHD (plant homeodomain)-type zinc finger that is critical for the enzymic activity of the histone acetyltransferase domain.…”

mentioning

confidence: 99%

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That zincing feeling: the effects of EDTA on the behaviour of zinc-binding transcriptional regulators

Nyborg

Peersen

2004

Biochemical Journal

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Zinc-binding proteins account for nearly half of the transcription regulatory proteins in the human genome and are the most abundant class of proteins in the human proteome. The zinc-binding transcriptional regulatory proteins utilize Zn 2+ to fold structural domains that participate in intermolecular interactions. A study by Matt et al. in this issue of the Biochemical Journal has examined the transcription factor binding properties of the zincbinding module C/H1 (cysteine/histidine-rich region 1) found in the transcriptional co-activator proteins CBP (CREB-binding protein) and p300. Their studies revealed that EDTA treatment of native C/H1 leads to irreversible denaturation and aggregation. Of particular concern is their finding that unfolded C/H1 participates in non-specific protein-protein interactions. The implications of these results are significant. EDTA is a very potent zinc-chelating agent that is used ubiquitously in protein interaction studies and in molecular biology in general. The potentially detrimental effects of EDTA on the structure and interactions of zinc-binding proteins should be taken into account in the interpretation of a sizeable number of published studies and must be considered in future experiments.Key words: CREB-binding protein (CBP), p300, chelation, denaturation, EDTA, transcription factor, zinc-binding domain, zinc finger.Zinc-binding proteins represent the largest and most complex gene superfamily in metazoans and comprise the most common class of transcription factors. Close to one thousand Cys2His2-type zinc-finger transcription factors are encoded by the human genome, representing nearly half of the hypothetical genes involved in the regulation of gene expression [1]. These zinc-binding proteins include co-activators, chromatin-modifying and -remodelling enzymes, a large number of DNA-binding transcription factors, members of the general transcription machinery and multisubunit RNA polymerases. The importance of zinc in gene expression cannot be overstated.The extensively homologous cellular co-activators CBP (CREB-binding protein) and p300 (CBP/p300) are prominent members of the zinc-binding superfamily. These very large cellular co-activators appear to play a role in the integration of gene expression in all metazoans. Over 1500 papers characterizing the physical and functional properties of CBP/p300 have been published during the last decade. Based on a large body of protein-protein interaction data, CBP/p300 have been suggested to carry out their co-activator function via direct binding to a vast number of structurally unrelated transcription regulators. The protein-protein interactions occur through several conserved domains within CBP/p300. Prominent among these are cysteine/ histidine-rich regions 1 and 3 (C/H1 and C/H3), each of which contains cysteine/histidine-rich sequences that co-ordinate three Zn 2+ atoms. These well-characterized domains form Zn 2+ -dependent helical fold structures that stabilize intermolecular interactions and mediate the recruitment of CBP...

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supporting

confidence: 93%

supporting

confidence: 92%

mentioning

confidence: 99%

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That zincing feeling: the effects of EDTA on the behaviour of zinc-binding transcriptional regulators

Nyborg

Peersen

2004

Biochemical Journal

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“…37,38 Upon binding FIH-1, the CAD becomes structured and engages the FIH-1 homodimer at two sites of interaction; site 1 in hHIF-1a-CAD encompasses residues 795-806 and contains the hydroxylated asparagine, while site 2 includes residues 812-823 and shows only weak binding independent of site 1 ( Figure 5). 39 Site 1 binds via 10 hydrogen bonds in an extended loop conformation, and site 2 residues form an a-helix.…”

Section: Oxygen-dependent Regulation Of Hif-cad By Fih-1mentioning

confidence: 99%

Turn me on: regulating HIF transcriptional activity

2008

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The hypoxia-inducible factors (HIFs) are critical for cellular adaptation to limiting oxygen and regulate a wide array of genes when cued by cellular oxygen-sensing mechanisms. HIF is able to direct transcription from either of two transactivation domains, each of which is regulated by distinct mechanisms. The oxygen-dependent asparaginyl hydroxylase factor-inhibiting HIF-1a (FIH-1) is a key regulator of the HIF C-terminal transactivation domain, and provides a direct link between oxygen sensation and HIFmediated transcription. Additionally, there are phosphorylation and nitrosylation events reported to modulate HIF transcriptional activity, as well as numerous transcriptional coactivators and other interacting proteins that together provide cell and tissue specificity of HIF target gene regulation. The maintenance of oxygen homeostasis is a crucial physiological requirement that involves coordinated regulation of a plethora of genes. The hypoxia-inducible transcription factors (HIFs) are responsible for a major genomic response to hypoxia, where cellular oxygen demand exceeds supply. The HIFs directly regulate the transcription of more than 70 genes involved in cellular processes that act to directly address this deficit by decreasing oxygen dependence and consumption by cells, and by increasing the efficiency of oxygen delivery to cells. These processes include vasculogenesis and angiogenesis, metabolism, vasodilation, cell migration, signalling and cell fate decisions. As such, the HIFs are fundamental to embryonic development and the pathophysiology of many serious human diseases, and are therefore subject to strict regulatory mechanisms that act to limit transcriptional activity to periods of cellular oxygen stress. The HIF proteins are subject to oxygen-dependent regulation, both at the level of protein stability (reviewed in this issue by R Bruick) and transcriptional activity, rendering them almost inactive at normoxia, but potently inducible in hypoxia. The regulation of the transcriptional activity of the HIF proteins, both via oxygen-dependent and oxygen-independent mechanisms, will be discussed in this review. The HIFsHIF is assembled from a-and b-subunits to become a transcriptionally active heterodimer. 1 Both subunits are members of the bHLH/PAS (basic helix-loop-helix/Per-ArntSim homology) family of transcription factors, and both contain transactivation domains (Figure 1). 2,3 Whereas HIF1b, also known as the aryl hydrocarbon receptor nuclear translocator (Arnt1), is a constitutively expressed nuclear protein, the a-subunit is strictly regulated in an oxygendependent manner. There are three paralogues of the HIF-a subunit, HIF-1a, HIF-2a and HIF-3a, and three paralogues of HIF-1b (Arnt1, Arnt2 and Arnt3), with either HIF-1a or HIF-2a being able to heterodimerize with HIF-1b to form the functional HIF transcription factor complexes responsible for the hypoxic shift in gene expression. HIF-3a has no known role as an active transcription factor, and is instead postulated to behave as a negative reg...

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“…[33][34][35] This prevents HIF from interacting with the transcriptional coactivators p300 and CREB-binding protein (CBP), thereby reducing the transactivating activity of HIF. 36,37 Under hypoxia, however, HIFa is not hydroxylated by either PHDs or FIH. The lack of prolyl hydroxylation prevents pVHL from recognizing HIFa and targeting it for proteasomal degradation.…”

Section: Regulation Of Hif Functionmentioning

confidence: 99%

Mitochondrial complex III regulates hypoxic activation of HIF

2008

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Decreases in oxygen levels are observed in physiological processes, such as development, and pathological situations, such as tumorigenesis and ischemia. In the complete absence of oxygen (anoxia), mammalian cells are unable to generate sufficient energy for survival, so a mechanism for sensing a decrease in the oxygen level (hypoxia) before it reaches a critical point is crucial for the survival of the organism. In response to decreased oxygen levels, cells activate the transcription factors hypoxiainducible factors (HIFs), which lead to metabolic adaptation to hypoxia, as well as to generate new vasculature to increase oxygen supply. How cells sense decreases in oxygen levels to regulate HIF activation has been hotly debated. Emerging evidence indicates that reactive oxygen species (ROS) generated by mitochondrial complex III are required for hypoxic activation of HIF. This review examines the current knowledge about the role of mitochondrial ROS in HIF activation, as well as implications of ROS-level regulation in pathological processes such as cancer. Oxygen Homeostasis and HIF Maintaining oxygen homeostasis is critical for survival and proper function of cells and organisms. 1 Reduced oxygen levels (hypoxia) initiates proper placental and vascular development. Hypoxia also has a causal role in pathological conditions such as ischemia-related diseases and cancer. A complete absence of oxygen (anoxia) results in cell death. 2 ATP synthesis is ablated, and most cells undergo apoptosis soon after anoxia exposure. 3-5 Cells exposed to hypoxia, or reduced oxygen levels, on the other hand, are able to maintain normal ATP synthesis and survive. 5,6 However, as cells replicate in a hypoxic environment, they reduce the oxygen supply even further and generate levels of local anoxia. Therefore, cells must respond quickly to decreasing oxygen levels before reaching an anoxic state (Figure 1).Mammalian cells respond to hypoxia by activating broadaction transcription factors named hypoxia-inducible factors, or HIFs, which are expressed by virtually all cells of the body. 7-9 Three members of the HIF family exist, named HIF1, HIF2 and HIF-3. 10-13 HIFs bind to hypoxia-responsive elements, consensus sequences in the promoter region of more than one hundred genes, activating the transcription of genes that allow the cell to adapt to and survive in the hypoxic environment. 14,15 Genes regulated by HIFs include glucose transporter that allow the cells to efficiently import glucose to continue generating ATP despite reduced nutrient availability; and genes that reorganize the microenvironment to bring in oxygen, such as vascular endothelial growth factor, which stimulates formation of new blood vessels. [16][17][18] Importantly for tumorigenesis, HIF also turns on genes such as insulin-like growth factor 2,19 which induces cellular survival and proliferation, as well as those that promote tumor invasion and migration, such as matrix metalloproteinase-2. 20 These factors contribute to tumor growth and invasion and metastasis, im...

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Structural basis for recruitment of CBP/p300 by hypoxia-inducible factor-1α

Cited by 417 publications

References 42 publications

That zincing feeling: the effects of EDTA on the behaviour of zinc-binding transcriptional regulators

That zincing feeling: the effects of EDTA on the behaviour of zinc-binding transcriptional regulators

Turn me on: regulating HIF transcriptional activity

Mitochondrial complex III regulates hypoxic activation of HIF

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