View source for 7rht


==Importin alpha 7 delta IBB (KPNA6)==
<StructureSection load='7rht' size='340' side='right'caption='[[7rht]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7rht]] is a 1 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=7RHT OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7RHT 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]] 2.5&#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=7rht FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7rht OCA], [https://pdbe.org/7rht PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7rht RCSB], [https://www.ebi.ac.uk/pdbsum/7rht PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7rht ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/IMA7_HUMAN IMA7_HUMAN] Functions in nuclear protein import as an adapter protein for nuclear receptor KPNB1. Binds specifically and directly to substrates containing either a simple or bipartite NLS motif. Docking of the importin/substrate complex to the nuclear pore complex (NPC) is mediated by KPNB1 through binding to nucleoporin FxFG repeats and the complex is subsequently translocated through the pore by an energy requiring, Ran-dependent mechanism. At the nucleoplasmic side of the NPC, Ran binds to importin-beta and the three components separate and importin-alpha and -beta are re-exported from the nucleus to the cytoplasm where GTP hydrolysis releases Ran from importin. The directionality of nuclear import is thought to be conferred by an asymmetric distribution of the GTP- and GDP-bound forms of Ran between the cytoplasm and nucleus.<ref>PMID:10523667</ref> 
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== Publication Abstract from PubMed ==
Shuttling of macromolecules between nucleus and cytoplasm is a tightly regulated process mediated through specific interactions between cargo and nuclear transport proteins. In the classical nuclear import pathway, importin alpha recognizes cargo exhibiting a nuclear localization signal, and this complex is transported through the nuclear pore complex by importin beta. Humans possess seven importin alpha isoforms that can be grouped into three subfamilies, with many cargoes displaying specificity towards these importin alpha isoforms. The cargo binding sites within importin alpha isoforms are highly conserved in sequence, suggesting that specificity potentially relies on structural differences. Structures of some importin alpha isoforms, both in cargo-bound and free states, have been previously solved. However, there are currently no known structures of cargo free importin alpha isoforms within subfamily 3 (importin alpha 5, 6, 7). Here, we present the first crystal structure of human importin alpha 7 lacking the IBB domain solved at 2.5 A resolution. The structure reveals a typical importin alpha architecture comprised of ten armadillo repeats and is most structurally conserved with importin alpha 5. Very little difference in structure was observed between the cargo-bound and free states, implying that importin alpha 7 does not undergo conformational change when binding cargo. These structural insights provide a strong platform for further evaluation of structure-function relationships and understanding how isoform specificity within the importin alpha family plays a role in nuclear transport in health and disease.

Structural characterization of human importin alpha 7 in its cargo-free form at 2.5 A resolution.,Tsimbalyuk S, Donnelly CM, Forwood JK Sci Rep. 2022 Jan 10;12(1):315. doi: 10.1038/s41598-021-03729-3. PMID:35013395<ref>PMID:35013395</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Importin 3D structures|Importin 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Forwood JK]]
[[Category: Tsimbalyuk S]]