National Institutes of Health/National Cancer Institute (NIH/NCI)
U54 CA132378
米国
National Institutes of Health/National Cancer Institute (NIH/NCI)
U54 C137788
米国
The G. Harold and Leila Y. Mathers Foundation
MF-2112-02288
米国
引用
ジャーナル: bioRxiv / 年: 2025 タイトル: Context-Dependent Variability Of HIF Heterodimers Influences Interactions With Macromolecular And Small Molecule Partners. 著者: Joseph D Closson / Xingjian Xu / Meiling Zhang / Tarsisius T Tiyani / Leandro Pimentel Marcelino / Eta A Isiorho / Jason S Nagati / Joseph A Garcia / Kevin H Gardner 要旨: Hypoxia inducible factors (HIFs) are transcription factors that coordinate cellular responses to low oxygen levels, functioning as an α/β heterodimer which binds a short hypoxia response element ...Hypoxia inducible factors (HIFs) are transcription factors that coordinate cellular responses to low oxygen levels, functioning as an α/β heterodimer which binds a short hypoxia response element (HRE) DNA sequence. Prior studies suggest HIF/HRE complexes are augmented by the binding of additional factors nearby, but those interactions are not well understood. Here, we integrated structural and biochemical approaches to investigate several functionally relevant HIF assemblies with other protein, small molecule, and DNA partners. First, we used cryo-electron microscopy (cryo-EM) to establish HIF-1 and HIF-2 form novel "dimer-of-heterodimers" (DoHD) complexes on extended human EPO enhancer sequences, showing that one heterodimer bound at a canonical HRE site with the second binding in an inverted fashion to an HRE-adjacent sequence (HAS) 8 bp away. Consistent with ARNT PAS-B domains predominating interactions within a DoHD, we found HIF-1 and HIF-2 assemble mixed DoHD complexes on the same DNA. Second, we saw substantial variability among ligands for isolated ARNT or HIF-2α PAS-B domains to bind larger complexes: for example, the ARNT PAS-B binding KG-548 and KG-279 ligands both bound the simpler HIF-2 heterodimer but exhibited differential binding to a HIF-2 DoHD. Finally, we combined cryo-EM and hydrogen-deuterium exchange by mass spectrometry (HDX-MS) to show how HIF-1 and HIF-2 heterodimers engage the transforming acidic coiled-coil containing protein 3 (TACC3) coactivator via both ARNT and HIF-α subunits, though this was unseen in the larger DoHD. Our findings highlight the importance of both molecular context and dynamics in biomolecular complex formation, adding to the complexities of potential regulation. SIGNIFICANCE STATEMENT: Hypoxia inducible factors (HIFs) are transcription factors that regulate oxygen-dependent cellular processes with implications in certain types of cancers. Current molecular ...SIGNIFICANCE STATEMENT: Hypoxia inducible factors (HIFs) are transcription factors that regulate oxygen-dependent cellular processes with implications in certain types of cancers. Current molecular structures of HIFs bound to short DNA fragments provide insights into their function, but leave open questions about how they bind longer natural DNA fragments and interact with small molecules and protein coactivators. Integrating structural and biochemical techniques, we discovered a novel assembly in which two HIFs bind together on a single extended DNA fragment, forming a "dimer-of-heterodimers", and ascertained how structural differences arising from higher-ordered complex formation affect ligand and coactivator binding. Our studies highlight how functional contexts can shift structural paradigms and provide greater insight into the mechanisms by which HIFs and similar transcription factors operate.
A: Endothelial PAS domain-containing protein 1 B: Aryl hydrocarbon receptor nuclear translocator C: 20-nt Hypoxia Response Element DNA (Forward) D: 20-nt Hypoxia Response Element DNA (Reverse)
EndothelialPASdomain-containingprotein1 / EPAS-1 / Basic-helix-loop-helix-PAS protein MOP2 / Class E basic helix-loop-helix protein 73 / ...EPAS-1 / Basic-helix-loop-helix-PAS protein MOP2 / Class E basic helix-loop-helix protein 73 / bHLHe73 / HIF-1-alpha-like factor / HLF / Hypoxia-inducible factor 2-alpha / HIF-2-alpha / HIF2-alpha / Member of PAS protein 2 / PAS domain-containing protein 2
分子量: 6527.181 Da / 分子数: 1 / 由来タイプ: 合成 / 由来: (合成) Homo sapiens (ヒト)
#4: DNA鎖
20-ntHypoxiaResponseElementDNA (Reverse)
分子量: 6363.116 Da / 分子数: 1 / 由来タイプ: 合成 / 由来: (合成) Homo sapiens (ヒト)
Has protein modification
N
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実験情報
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実験
実験
手法: 電子顕微鏡法
EM実験
試料の集合状態: PARTICLE / 3次元再構成法: 単粒子再構成法
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試料調製
構成要素
名称: Hypoxia inducible factor 2-alpha and aryl hydrocarbon nuclear translocator complexed on hypoxia response element DNA タイプ: COMPLEX / Entity ID: all / 由来: RECOMBINANT