View source for 6sqo


==Crystal structure of human MDM2 RING domain homodimer bound to UbcH5B-Ub==
<StructureSection load='6sqo' size='340' side='right'caption='[[6sqo]], [[Resolution|resolution]] 1.41&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6sqo]] is a 6 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=6SQO OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6SQO 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]] 1.41&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=NO3:NITRATE+ION'>NO3</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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=6sqo FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6sqo OCA], [https://pdbe.org/6sqo PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6sqo RCSB], [https://www.ebi.ac.uk/pdbsum/6sqo PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6sqo ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/MDM2_HUMAN MDM2_HUMAN] Note=Seems to be amplified in certain tumors (including soft tissue sarcomas, osteosarcomas and gliomas). A higher frequency of splice variants lacking p53 binding domain sequences was found in late-stage and high-grade ovarian and bladder carcinomas. Four of the splice variants show loss of p53 binding.
== Function ==
[https://www.uniprot.org/uniprot/MDM2_HUMAN MDM2_HUMAN] E3 ubiquitin-protein ligase that mediates ubiquitination of p53/TP53, leading to its degradation by the proteasome. Inhibits p53/TP53- and p73/TP73-mediated cell cycle arrest and apoptosis by binding its transcriptional activation domain. Also acts as an ubiquitin ligase E3 toward itself and ARRB1. Permits the nuclear export of p53/TP53. Promotes proteasome-dependent ubiquitin-independent degradation of retinoblastoma RB1 protein. Inhibits DAXX-mediated apoptosis by inducing its ubiquitination and degradation. Component of the TRIM28/KAP1-MDM2-p53/TP53 complex involved in stabilizing p53/TP53. Also component of the TRIM28/KAP1-ERBB4-MDM2 complex which links growth factor and DNA damage response pathways. Mediates ubiquitination and subsequent proteasome degradation of DYRK2 in nucleus. Ubiquitinates IGF1R and promotes it to proteasomal degradation.<ref>PMID:12821780</ref> <ref>PMID:15053880</ref> <ref>PMID:15195100</ref> <ref>PMID:16337594</ref> <ref>PMID:15632057</ref> <ref>PMID:17290220</ref> <ref>PMID:19098711</ref> <ref>PMID:19219073</ref> <ref>PMID:19965871</ref> <ref>PMID:20858735</ref> <ref>PMID:20173098</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Phosphorylation of MDM2 by ATM upon DNA damage is an important mechanism for deregulating MDM2, thereby leading to p53 activation. ATM phosphorylates multiple residues near the RING domain of MDM2, but the underlying molecular basis for deregulation remains elusive. Here we show that Ser429 phosphorylation selectively enhances the ubiquitin ligase activity of MDM2 homodimer but not MDM2-MDMX heterodimer. A crystal structure of phospho-Ser429 (pS429)-MDM2 bound to E2-ubiquitin reveals a unique 310-helical feature present in MDM2 homodimer that allows pS429 to stabilize the closed E2-ubiquitin conformation and thereby enhancing ubiquitin transfer. In cells Ser429 phosphorylation increases MDM2 autoubiquitination and degradation upon DNA damage, whereas S429A substitution protects MDM2 from auto-degradation. Our results demonstrate that Ser429 phosphorylation serves as a switch to boost the activity of MDM2 homodimer and promote its self-destruction to enable rapid p53 stabilization and resolve a long-standing controversy surrounding MDM2 auto-degradation in response to DNA damage.

Structural basis for DNA damage-induced phosphoregulation of MDM2 RING domain.,Magnussen HM, Ahmed SF, Sibbet GJ, Hristova VA, Nomura K, Hock AK, Archibald LJ, Jamieson AG, Fushman D, Vousden KH, Weissman AM, Huang DT Nat Commun. 2020 Apr 29;11(1):2094. doi: 10.1038/s41467-020-15783-y. PMID:32350255<ref>PMID:32350255</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6sqo" style="background-color:#fffaf0;"></div>

==See Also==
*[[MDM2 3D structures|MDM2 3D structures]]
*[[3D structures of ubiquitin conjugating enzyme|3D structures of ubiquitin conjugating enzyme]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Ahmed SF]]
[[Category: Huang DT]]
[[Category: Magnussen HM]]