View source for 6to5


==Crystal structure of the oligomerisation domain of the transcription factor PHOSPHATE STARVATION RESPONSE 1 from Arabidopsis.==
<StructureSection load='6to5' size='340' side='right'caption='[[6to5]], [[Resolution|resolution]] 2.38&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6to5]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Arabidopsis_thaliana Arabidopsis thaliana]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6TO5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6TO5 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.38&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=6to5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6to5 OCA], [https://pdbe.org/6to5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6to5 RCSB], [https://www.ebi.ac.uk/pdbsum/6to5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6to5 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/PHR1_ARATH PHR1_ARATH] Transcription factor involved in phosphate starvation signaling (PubMed:11511543, PubMed:17927693, PubMed:26586833). Binds as a dimer to P1BS, an imperfect palindromic sequence 5'-GNATATNC-3', to promote the expression of inorganic phosphate (Pi) starvation-responsive genes (PubMed:11511543, PubMed:20838596, PubMed:26586833). SPX1 is a competitive inhibitor of this DNA-binding (PubMed:25271326). PHR1 binding to its targets is low Pi-dependent (PubMed:25271326). Regulates the expression of miR399 (PubMed:20838596). Regulates the expression of IPS1 (At3g09922), a non-coding RNA that mimics the target of miR399 to block the cleavage of PHO2 under Pi-deficient conditions (PubMed:17643101). Regulates lipid remodeling and triacylglycerol accumulation during phosphorus starvation (PubMed:25680792). Required for the shoot-specific hypoxic response (PubMed:24753539). Regulates FER1 expression upon phosphate starvation, linking iron and phosphate homeostasis (PubMed:23788639). Contributes to the homeostasis of both sulfate and phosphate in plants under phosphate deficiency (PubMed:21261953). Required for adaptation to high light and retaining functional photosynthesis during phosphate starvation (PubMed:21910737). Involved in the coregulation of Zn and Pi homeostasis (PubMed:24420568).<ref>PMID:11511543</ref> <ref>PMID:17643101</ref> <ref>PMID:17927693</ref> <ref>PMID:20838596</ref> <ref>PMID:21261953</ref> <ref>PMID:21910737</ref> <ref>PMID:23788639</ref> <ref>PMID:24420568</ref> <ref>PMID:24753539</ref> <ref>PMID:25271326</ref> <ref>PMID:25680792</ref> <ref>PMID:26586833</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Phosphorus is an essential nutrient taken up by organisms in the form of inorganic phosphate (Pi). Eukaryotes have evolved sophisticated Pi sensing and signaling cascades, enabling them to stably maintain cellular Pi concentrations. Pi homeostasis is regulated by inositol pyrophosphate signaling molecules (PP-InsPs), which are sensed by SPX domain-containing proteins. In plants, PP-InsP-bound SPX receptors inactivate Myb coiled-coil (MYB-CC) Pi starvation response transcription factors (PHRs) by an unknown mechanism. Here we report that a InsP(8)-SPX complex targets the plant-unique CC domain of PHRs. Crystal structures of the CC domain reveal an unusual four-stranded anti-parallel arrangement. Interface mutations in the CC domain yield monomeric PHR1, which is no longer able to bind DNA with high affinity. Mutation of conserved basic residues located at the surface of the CC domain disrupt interaction with the SPX receptor in vitro and in planta, resulting in constitutive Pi starvation responses. Together, our findings suggest that InsP(8) regulates plant Pi homeostasis by controlling the oligomeric state and hence the promoter binding capability of PHRs via their SPX receptors.

Inositol pyrophosphates promote the interaction of SPX domains with the coiled-coil motif of PHR transcription factors to regulate plant phosphate homeostasis.,Ried MK, Wild R, Zhu J, Pipercevic J, Sturm K, Broger L, Harmel RK, Abriata LA, Hothorn LA, Fiedler D, Hiller S, Hothorn M Nat Commun. 2021 Jan 15;12(1):384. doi: 10.1038/s41467-020-20681-4. PMID:33452263<ref>PMID:33452263</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6to5" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Arabidopsis thaliana]]
[[Category: Large Structures]]
[[Category: Hothorn M]]