6if1

Structural highlights

Function

UBE2K_HUMAN Accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. In vitro, in the presence or in the absence of BRCA1-BARD1 E3 ubiquitin-protein ligase complex, catalyzes the synthesis of 'Lys-48'-linked polyubiquitin chains. Does not transfer ubiquitin directly to but elongates monoubiquitinated substrate protein. Mediates the selective degradation of short-lived and abnormal proteins, such as the endoplasmic reticulum-associated degradation (ERAD) of misfolded lumenal proteins. Ubiquitinates huntingtin. May mediate foam cell formation by the suppression of apoptosis of lipid-bearing macrophages through ubiquitination and subsequence degradation of p53/TP53. Proposed to be involved in ubiquitination and proteolytic processing of NF-kappa-B; in vitro supports ubiquitination of NFKB1. In case of infection by cytomegaloviruses may be involved in the US11-dependent degradation of MHC class I heavy chains following their export from the ER to the cytosol. In case of viral infections may be involved in the HPV E7 protein-dependent degradation of RB1.^{[1] [2] [3] [4] [5] [6] [7] [8]}

See Also

• 3D structures of ubiquitin
• 3D structures of ubiquitin conjugating enzyme

References

1. ↑ Kalchman MA, Graham RK, Xia G, Koide HB, Hodgson JG, Graham KC, Goldberg YP, Gietz RD, Pickart CM, Hayden MR. Huntingtin is ubiquitinated and interacts with a specific ubiquitin-conjugating enzyme. J Biol Chem. 1996 Aug 9;271(32):19385-94. PMID:8702625
2. ↑ Kikuchi J, Furukawa Y, Kubo N, Tokura A, Hayashi N, Nakamura M, Matsuda M, Sakurabayashi I. Induction of ubiquitin-conjugating enzyme by aggregated low density lipoprotein in human macrophages and its implications for atherosclerosis. Arterioscler Thromb Vasc Biol. 2000 Jan;20(1):128-34. PMID:10634809
3. ↑ Furukawa Y, Kubo N, Kikuchi J, Tokura A, Fujita N, Sakurabayashi I. Regulation of macrophage-specific gene expression by degenerated lipoproteins. Electrophoresis. 2000 Jan;21(2):338-46. PMID:10675012 doi:<338::AID-ELPS338>3.0.CO;2-9 http://dx.doi.org/10.1002/(SICI)1522-2683(20000101)21:2<338::AID-ELPS338>3.0.CO;2-9
4. ↑ Yamada M, Ohnishi J, Ohkawara B, Iemura S, Satoh K, Hyodo-Miura J, Kawachi K, Natsume T, Shibuya H. NARF, an nemo-like kinase (NLK)-associated ring finger protein regulates the ubiquitylation and degradation of T cell factor/lymphoid enhancer factor (TCF/LEF). J Biol Chem. 2006 Jul 28;281(30):20749-60. Epub 2006 May 19. PMID:16714285 doi:http://dx.doi.org/10.1074/jbc.M602089200
5. ↑ Flierman D, Coleman CS, Pickart CM, Rapoport TA, Chau V. E2-25K mediates US11-triggered retro-translocation of MHC class I heavy chains in a permeabilized cell system. Proc Natl Acad Sci U S A. 2006 Aug 1;103(31):11589-94. Epub 2006 Jul 25. PMID:16868077 doi:http://dx.doi.org/0605215103
6. ↑ Christensen DE, Brzovic PS, Klevit RE. E2-BRCA1 RING interactions dictate synthesis of mono- or specific polyubiquitin chain linkages. Nat Struct Mol Biol. 2007 Oct;14(10):941-8. Epub 2007 Sep 16. PMID:17873885 doi:http://dx.doi.org/10.1038/nsmb1295
7. ↑ David Y, Ziv T, Admon A, Navon A. The E2 ubiquitin conjugating enzymes direct polyubiquitination to preferred lysines. J Biol Chem. 2010 Jan 8. PMID:20061386 doi:M109.089003
8. ↑ Oh KJ, Kalinina A, Bagchi S. Destabilization of Rb by human papillomavirus E7 is cell cycle dependent: E2-25K is involved in the proteolysis. Virology. 2010 Jan 5;396(1):118-24. doi: 10.1016/j.virol.2009.10.018. Epub 2009, Nov 10. PMID:19906396 doi:http://dx.doi.org/10.1016/j.virol.2009.10.018
9. ↑ Lee JG, Youn HS, Kang JY, Park SY, Kidera A, Yoo YJ, Eom SH. Crystal structure of the Ube2K/E2-25K and K48-linked di-ubiquitin complex provides structural insight into the mechanism of K48-specific ubiquitin chain synthesis. Biochem Biophys Res Commun. 2018 Nov 17;506(1):102-107. PMID:30336976 doi:10.1016/j.bbrc.2018.10.067