IUBMB Enzyme Nomenclature


Accepted name: RING-type E3 ubiquitin transferase

Reaction: [E2 ubiquitin-conjugating enzyme]-S-ubiquitinyl-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-N6-ubiquitinyl-L-lysine

Glossary: RING = Really Interesting New Gene

Other name(s): RING E3 ligase (misleading); ubiquitin transferase RING E3; S-ubiquitinyl-[ubiquitin-conjugating E2 enzyme]-L-cysteine:acceptor protein ubiquitin transferase (isopeptide bond-forming, RING-type)

Systematic name: [E2 ubiquitin-conjugating enzyme]-S-ubiquitinyl-L-cysteine:[acceptor protein] ubiquitin transferase (isopeptide bond-forming; RING-type)

Comments: RING E3 ubiquitin transferases serve as mediators bringing the ubiquitin-charged E2 ubiquitin-conjugating enzyme (EC and an acceptor protein together to enable the direct transfer of ubiquitin through the formation of an isopeptide bond between the C-terminal glycine residue of ubiquitin and the ε-amino group of an L-lysine residue of the acceptor protein. Unlike EC, HECT-type E3 ubiquitin transferase, the RING-E3 domain does not form a catalytic thioester intermediate with ubiquitin. Many members of the RING-type E3 ubiquitin transferase family are not able to bind a substrate directly, and form a complex with a cullin scaffold protein and a substrate recognition module (the complexes are named CRL for Cullin-RING-Ligase). In these complexes, the RING-type E3 ubiquitin transferase provides an additional function, mediating the transfer of a NEDD8 protein from a dedicated E2 carrier to the cullin protein (see EC, cullin-RING-type E3 NEDD8 transferase). cf. EC, RBR-type E3 ubiquitin transferase.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:


1. Eisele, F. and Wolf, D.H. Degradation of misfolded protein in the cytoplasm is mediated by the ubiquitin ligase Ubr1. FEBS Lett. 582 (2008) 4143-4146. [PMID: 19041308]

2. Metzger, M.B., Hristova, V.A. and Weissman, A.M. HECT and RING finger families of E3 ubiquitin ligases at a glance. J. Cell Sci. 125 (2012) 531-537. [PMID: 22389392]

3. Plechanovova, A., Jaffray, E.G., Tatham, M.H., Naismith, J.H. and Hay, R.T. Structure of a RING E3 ligase and ubiquitin-loaded E2 primed for catalysis. Nature 489 (2012) 115-120. [PMID: 22842904]

4. Pruneda, J.N., Littlefield, P.J., Soss, S.E., Nordquist, K.A., Chazin, W.J., Brzovic, P.S. and Klevit, R.E. Structure of an E3:E2~Ub complex reveals an allosteric mechanism shared among RING/U-box ligases. Mol. Cell 47 (2012) 933-942. [PMID: 22885007]

5. Metzger, M.B., Pruneda, J.N., Klevit, R.E. and Weissman, A.M. RING -type E3 ligases: master manipulators of E2 ubiquitin-conjugating enzymes and ubiquitination. Biochim. Biophys. Acta 1843 (2014) 47-60. [PMID: 23747565]

[EC created 2015, modified 2017]

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