View source for 2a24

==HADDOCK Structure of HIF-2a/ARNT PAS-B Heterodimer==
<StructureSection load='2a24' size='340' side='right' caption='[[2a24]], [[NMR_Ensembles_of_Models | 20 NMR models]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2a24]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2A24 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2A24 FirstGlance]. <br>
</td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2a24 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2a24 OCA], [http://pdbe.org/2a24 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2a24 RCSB], [http://www.ebi.ac.uk/pdbsum/2a24 PDBsum]</span></td></tr>
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== Disease ==
[[http://www.uniprot.org/uniprot/EPAS1_HUMAN EPAS1_HUMAN]] Defects in EPAS1 are the cause of familial erythrocytosis type 4 (ECYT4) [MIM:[http://omim.org/entry/611783 611783]]. ECYT4 is an autosomal dominant disorder characterized by increased serum red blood cell mass, elevated hemoglobin concentration and hematocrit, and normal platelet and leukocyte counts.<ref>PMID:19208626</ref> <ref>PMID:18378852</ref> <ref>PMID:18184961</ref> <ref>PMID:22367913</ref>  
== Function ==
[[http://www.uniprot.org/uniprot/EPAS1_HUMAN EPAS1_HUMAN]] Transcription factor involved in the induction of oxygen regulated genes. Binds to core DNA sequence 5'-[AG]CGTG-3' within the hypoxia response element (HRE) of target gene promoters. Regulates the vascular endothelial growth factor (VEGF) expression and seems to be implicated in the development of blood vessels and the tubular system of lung. May also play a role in the formation of the endothelium that gives rise to the blood brain barrier. Potent activator of the Tie-2 tyrosine kinase expression. Activation seems to require recruitment of transcriptional coactivators such as CREBPB and probably EP300. Interaction with redox regulatory protein APEX seems to activate CTAD. [[http://www.uniprot.org/uniprot/ARNT_HUMAN ARNT_HUMAN]] Required for activity of the Ah (dioxin) receptor. This protein is required for the ligand-binding subunit to translocate from the cytosol to the nucleus after ligand binding. The complex then initiates transcription of genes involved in the activation of PAH procarcinogens. The heterodimer with HIF1A or EPAS1/HIF2A functions as a transcriptional regulator of the adaptive response to hypoxia. 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/a2/2a24_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2a24 ConSurf].
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== Publication Abstract from PubMed ==
The aryl hydrocarbon receptor nuclear translocator (ARNT) is a promiscuous bHLH-PAS (Per-ARNT-Sim) protein that forms heterodimeric transcriptional regulator complexes with several other bHLH-PAS subunits to control a variety of biological pathways, some of which are centrally involved in disease initiation and/or progression. One of these is the hypoxia response pathway, which allows eukaryotic cells to respond to low oxygen tension via the formation of a heterodimeric complex between ARNT and another bHLH-PAS protein, the hypoxia-inducible factor alpha (HIF-alpha). We have previously shown that the C-terminal PAS domains of an HIF-alpha isoform (HIF-2alpha) and ARNT interact in vitro, and that mutations in the solvent-exposed beta-sheet surface of the HIF-2alpha domain not only disrupt this interaction, but also greatly attenuate the hypoxia response in living cells. Here, we have solved the solution structure of the corresponding PAS domain of ARNT and show that it utilizes a very similar interface for the interaction with the HIF-2alpha PAS domain. We also show that this domain self-associates in a concentration-dependent manner, and that the interface used in this homodimeric complex is very similar to that used in the formation of heterodimer. In addition, using experimentally derived NMR restraints, we used the program HADDOCK to calculate a low-resolution model of the complex formed in solution by these two PAS domains, and confirm the validity of this model using site-directed spin labeling to obtain long-range distance information in solution. With this information, we propose a model for the mode of multi-PAS domain interaction in bHLH-PAS transcriptional activation complexes.

Structural basis of ARNT PAS-B dimerization: use of a common beta-sheet interface for hetero- and homodimerization.,Card PB, Erbel PJ, Gardner KH J Mol Biol. 2005 Oct 28;353(3):664-77. Epub 2005 Sep 6. PMID:16181639<ref>PMID:16181639</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Factor inhibiting HIF|Factor inhibiting HIF]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Card, P B]]
[[Category: Erbel, P J]]
[[Category: Gardner, K H]]
[[Category: Arnt]]
[[Category: Hif]]
[[Category: Hypoxia]]
[[Category: Pa]]
[[Category: Transcription]]