EC - RING-type E3 ubiquitin transferase (cysteine targeting)

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IntEnz Enzyme Nomenclature


Accepted name:
RING-type E3 ubiquitin transferase (cysteine targeting)
Other name:
RING E3 ligase [misleading]
Systematic name:
[E2 ubiquitin-conjugating enzyme]-S-ubiquitinyl-L-cysteine:[acceptor protein] ubiquitin transferase (thioester bond-froming; RING-type)



This relatively rare subpopulation of RING-type E3 ubiquitin transferases (cf. EC, found in mammals and herpes viruses, can transfer ubiquitin to a cysteine residue in target proteins. Additional ubiquitin molecules are polymerized on top of the initial ubiquitin molecule by formation of an isopeptide linkage with lysine48 in the pre-attached ubiquitin [2].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB


  1. Cadwell, K., Coscoy, L.
    Ubiquitination on nonlysine residues by a viral E3 ubiquitin ligase.
    Science 309 : 127-130 (2005). [PMID: 15994556]
  2. Wang, Y. J., Bian, Y., Luo, J., Lu, M., Xiong, Y., Guo, S. Y., Yin, H. Y., Lin, X., Li, Q., Chang, C. C. Y., Chang, T. Y., Li, B. L., Song, B. L.
    Cholesterol and fatty acids regulate cysteine ubiquitylation of ACAT2 through competitive oxidation.
    Nat Cell Biol 19 : 808-819 (2017). [PMID: 28604676]
  3. Zhou, Z. S., Li, M. X., Liu, J., Jiao, H., Xia, J. M., Shi, X. J., Zhao, H., Chu, L., Liu, J., Qi, W., Luo, J., Song, B. L.
    Competitive oxidation and ubiquitylation on the evolutionarily conserved cysteine confer tissue-specific stabilization of Insig-2.
    Nat Commun 11 : 379 (2020). [PMID: 31953408]

[EC created 2020]