View source for 2lvq


==gp78CUE domain bound to the proximal ubiquitin of K48-linked diubiquitin==
<StructureSection load='2lvq' size='340' side='right'caption='[[2lvq]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2lvq]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2LVQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2LVQ FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</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=2lvq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2lvq OCA], [https://pdbe.org/2lvq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2lvq RCSB], [https://www.ebi.ac.uk/pdbsum/2lvq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2lvq ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/UBC_HUMAN UBC_HUMAN] Ubiquitin exists either covalently attached to another protein, or free (unanchored). When covalently bound, it is conjugated to target proteins via an isopeptide bond either as a monomer (monoubiquitin), a polymer linked via different Lys residues of the ubiquitin (polyubiquitin chains) or a linear polymer linked via the initiator Met of the ubiquitin (linear polyubiquitin chains). Polyubiquitin chains, when attached to a target protein, have different functions depending on the Lys residue of the ubiquitin that is linked: Lys-6-linked may be involved in DNA repair; Lys-11-linked is involved in ERAD (endoplasmic reticulum-associated degradation) and in cell-cycle regulation; Lys-29-linked is involved in lysosomal degradation; Lys-33-linked is involved in kinase modification; Lys-48-linked is involved in protein degradation via the proteasome; Lys-63-linked is involved in endocytosis, DNA-damage responses as well as in signaling processes leading to activation of the transcription factor NF-kappa-B. Linear polymer chains formed via attachment by the initiator Met lead to cell signaling. Ubiquitin is usually conjugated to Lys residues of target proteins, however, in rare cases, conjugation to Cys or Ser residues has been observed. When polyubiquitin is free (unanchored-polyubiquitin), it also has distinct roles, such as in activation of protein kinases, and in signaling.<ref>PMID:16543144</ref> <ref>PMID:19754430</ref> 
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== Publication Abstract from PubMed ==
Recognition of ubiquitin and polyubiquitin chains by ubiquitin-binding domains (UBDs) is vital for ubiquitin-mediated signaling pathways. The endoplasmic reticulum resident RING finger ubiquitin ligase (E3) gp78 regulates critical proteins via the ubiquitin-proteasome system to maintain cellular homeostasis and includes a UBD known as the CUE domain, which is essential for function. A probable role of this domain is to recognize ubiquitin-modified substrates, enabling gp78 to assemble polyubiquitin chains on these substrates and mark them for degradation. Here, we report the molecular details of the interaction of gp78CUE domain with ubiquitin and diubiquitin. The gp78CUE domain exhibits a well-defined set of interactions with ubiquitin and a dynamic, promiscuous interaction with diubiquitin chains. This leads to a model in which the CUE domain functions to both facilitate substrate binding and enable switching between adjacent ubiquitin molecules of a growing chain to enable processivity in ubiquitination.

Promiscuous Interactions of gp78 E3 Ligase CUE Domain with Polyubiquitin Chains.,Liu S, Chen Y, Li J, Huang T, Tarasov S, King A, Weissman AM, Byrd RA, Das R Structure. 2012 Oct 31. pii: S0969-2126(12)00373-5. doi:, 10.1016/j.str.2012.09.020. PMID:23123110<ref>PMID:23123110</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 2lvq" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ubiquitin protein ligase 3D structures|Ubiquitin protein ligase 3D structures]]
*[[3D structures of ubiquitin|3D structures of ubiquitin]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Byrd RA]]
[[Category: Chen Y]]
[[Category: Das R]]
[[Category: Huang T]]
[[Category: King A]]
[[Category: Li J]]
[[Category: Liu S]]
[[Category: Tarasov SG]]
[[Category: Weissman AM]]