| Structural highlights
Function
[UB2G2_MOUSE] Accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. In vitro catalyzes 'Lys-48'-linked polyubiquitination. Involved in endoplasmic reticulum-associated degradation (ERAD) (By similarity). [AMFR_HUMAN] E3 ubiquitin-protein ligase that mediates the polyubiquitination of a number of proteins such as CD3D, CYP3A4, CFTR and APOB for proteasomal degradation. Component of a VCP/p97-AMFR/gp78 complex that participates in the final step of endoplasmic reticulum-associated degradation (ERAD). The VCP/p97-AMFR/gp78 complex is involved in the sterol-accelerated ERAD degradation of HMGCR through binding to the HMGCR-INSIG complex at the ER membrane and initiating ubiquitination of HMGCR. The ubiquitinated HMGCR is then released from the ER by the complex into the cytosol for subsequent destruction. Also acts as a scaffold protein to assemble a complex that couples ubiquitination, retranslocation and deglycosylation. Mediates tumor invasion and metastasis as a receptor for the GPI/autocrine motility factor.[1] [2] [3] [4]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Lys-48-linked polyubiquitination regulates a variety of cellular processes by targeting ubiquitinated proteins to the proteasome for degradation. Although polyubiquitination had been presumed to occur by transferring ubiquitin molecules, one at a time, from an E2 active site to a substrate, we recently showed that the endoplasmic reticulum-associated RING finger ubiquitin ligase gp78 can mediate the preassembly of Lys-48-linked polyubiquitin chains on the catalytic cysteine of its cognate E2 Ube2g2 and subsequent transfer to a substrate. Active site-linked polyubiquitin chains are detected in cells on Ube2g2 and its yeast homolog Ubc7p, but how these chains are assembled is unclear. Here, we show that gp78 forms an oligomer via 2 oligomerization sites, one of which is a hydrophobic segment located in the gp78 cytosolic domain. We further demonstrate that a gp78 oligomer can simultaneously associate with multiple Ube2g2 molecules. This interaction is mediated by a novel Ube2g2 surface distinct from the predicted RING binding site. Our data suggest that a large gp78-Ube2g2 heterooligomer brings multiple Ube2g2 molecules into close proximity, allowing ubiquitin moieties to be transferred between neighboring Ube2g2s to form active site-linked polyubiquitin chains.
Mechanistic insights into active site-associated polyubiquitination by the ubiquitin-conjugating enzyme Ube2g2.,Li W, Tu D, Li L, Wollert T, Ghirlando R, Brunger AT, Ye Y Proc Natl Acad Sci U S A. 2009 Mar 10;106(10):3722-7. Epub 2009 Feb 17. PMID:19223579[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Shimizu K, Tani M, Watanabe H, Nagamachi Y, Niinaka Y, Shiroishi T, Ohwada S, Raz A, Yokota J. The autocrine motility factor receptor gene encodes a novel type of seven transmembrane protein. FEBS Lett. 1999 Aug 6;456(2):295-300. PMID:10456327
- ↑ Fang S, Ferrone M, Yang C, Jensen JP, Tiwari S, Weissman AM. The tumor autocrine motility factor receptor, gp78, is a ubiquitin protein ligase implicated in degradation from the endoplasmic reticulum. Proc Natl Acad Sci U S A. 2001 Dec 4;98(25):14422-7. Epub 2001 Nov 27. PMID:11724934 doi:10.1073/pnas.251401598
- ↑ Song BL, Sever N, DeBose-Boyd RA. Gp78, a membrane-anchored ubiquitin ligase, associates with Insig-1 and couples sterol-regulated ubiquitination to degradation of HMG CoA reductase. Mol Cell. 2005 Sep 16;19(6):829-40. PMID:16168377 doi:10.1016/j.molcel.2005.08.009
- ↑ Pabarcus MK, Hoe N, Sadeghi S, Patterson C, Wiertz E, Correia MA. CYP3A4 ubiquitination by gp78 (the tumor autocrine motility factor receptor, AMFR) and CHIP E3 ligases. Arch Biochem Biophys. 2009 Mar 1;483(1):66-74. doi: 10.1016/j.abb.2008.12.001., Epub 2008 Dec 10. PMID:19103148 doi:10.1016/j.abb.2008.12.001
- ↑ Li W, Tu D, Li L, Wollert T, Ghirlando R, Brunger AT, Ye Y. Mechanistic insights into active site-associated polyubiquitination by the ubiquitin-conjugating enzyme Ube2g2. Proc Natl Acad Sci U S A. 2009 Mar 10;106(10):3722-7. Epub 2009 Feb 17. PMID:19223579 doi:0808564106
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