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==Structure of an endogenous human TREX complex bound to mRNA==
<StructureSection load='7znk' size='340' side='right'caption='[[7znk]], [[Resolution|resolution]] 3.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7znk]] is a 32 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7ZNK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7ZNK FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.9&#8491;</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=7znk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7znk OCA], [https://pdbe.org/7znk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7znk RCSB], [https://www.ebi.ac.uk/pdbsum/7znk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7znk ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/THOC1_HUMAN THOC1_HUMAN] Component of the THO subcomplex of the TREX complex. The TREX complex specifically associates with spliced mRNA and not with unspliced pre-mRNA. It is recruited to spliced mRNAs by a transcription-independent mechanism. Binds to mRNA upstream of the exon-junction complex (EJC) and is recruited in a splicing- and cap-dependent manner to a region near the 5' end of the mRNA where it functions in mRNA export. The recruitment occurs via an interaction between ALYREF/THOC4 and the cap-binding protein NCBP1. DDX39B functions as a bridge between ALYREF/THOC4 and the THO complex. The TREX complex is essential for the export of Kaposi's sarcoma-associated herpesvirus (KSHV) intronless mRNAs and infectious virus production. The recruitment of the TREX complex to the intronless viral mRNA occurs via an interaction between KSHV ORF57 protein and ALYREF/THOC4.<ref>PMID:10512864</ref> <ref>PMID:10840029</ref> <ref>PMID:11050087</ref> <ref>PMID:11979277</ref> <ref>PMID:15833825</ref> <ref>PMID:15998806</ref> <ref>PMID:15870275</ref> <ref>PMID:17190602</ref> <ref>PMID:18974867</ref>   Regulates transcriptional elongation of a subset of genes. Participates in an apoptotic pathway which is characterized by activation of caspase-6, increases in the expression of BAK1 and BCL2L1 and activation of NF-kappa-B. This pathway does not require p53/TP53, nor does the presence of p53/TP53 affect the efficiency of cell killing. Activates a G2/M cell cycle checkpoint prior to the onset of apoptosis. Apoptosis is inhibited by association with RB1.<ref>PMID:10512864</ref> <ref>PMID:10840029</ref> <ref>PMID:11050087</ref> <ref>PMID:11979277</ref> <ref>PMID:15833825</ref> <ref>PMID:15998806</ref> <ref>PMID:15870275</ref> <ref>PMID:17190602</ref> <ref>PMID:18974867</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Newly made mRNAs are processed and packaged into mature ribonucleoprotein complexes (mRNPs) and are recognized by the essential transcription-export complex (TREX) for nuclear export(1,2). However, the mechanisms of mRNP recognition and three-dimensional mRNP organization are poorly understood(3). Here we report cryo-electron microscopy and tomography structures of reconstituted and endogenous human mRNPs bound to the 2-MDa TREX complex. We show that mRNPs are recognized through multivalent interactions between the TREX subunit ALYREF and mRNP-bound exon junction complexes. Exon junction complexes can multimerize through ALYREF, which suggests a mechanism for mRNP organization. Endogenous mRNPs form compact globules that are coated by multiple TREX complexes. These results reveal how TREX may simultaneously recognize, compact and protect mRNAs to promote their packaging for nuclear export. The organization of mRNP globules provides a framework to understand how mRNP architecture facilitates mRNA biogenesis and export.

mRNA recognition and packaging by the human transcription-export complex.,Pacheco-Fiallos B, Vorlander MK, Riabov-Bassat D, Fin L, O'Reilly FJ, Ayala FI, Schellhaas U, Rappsilber J, Plaschka C Nature. 2023 Apr;616(7958):828-835. doi: 10.1038/s41586-023-05904-0. Epub 2023 , Apr 5. PMID:37020021<ref>PMID:37020021</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7znk" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Pacheco-Fiallos FB]]
[[Category: Plaschka C]]
[[Category: Vorlaender MK]]