InterPro domain: IPR027230

SUMO proteins are ubiquitin like proteins that are covalently attached to and detached from other proteins in cells to modify their function. SUMO is first activated in an ATP-dependent reaction by formation of a thioester bond with an E1 (SUMO-activating) enzyme and then transferred to the SUMO conjugating (E2) enzyme Ubc9. Ubc9 catalyses the formation of an isopeptide bond between the C-terminal of SUMO and the amino group of lysine in the target protein. Sumoylated proteins can be targeted for different cellular processes, such as nuclear transport, transcriptional regulation, apoptosis, and protein stability [ 1 ].

This entry represents the SUMO-conjugating enzyme Ubc9 (also known as UBE2I) and its homologue in plants, SCE1 [ 2 , 3 , 4 , 5 , 6 ].

1. Molecular features of human ubiquitin-like SUMO genes and their encoded proteins. Gene 296, 65-73
2. Identification of the structural and functional human homolog of the yeast ubiquitin conjugating enzyme UBC9. Nucleic Acids Res. 24, 2005-10
3. Genetic analysis of SUMOylation in Arabidopsis: conjugation of SUMO1 and SUMO2 to nuclear proteins is essential. Plant Physiol. 145, 119-34
4. Ubc9p and the conjugation of SUMO-1 to RanGAP1 and RanBP2. Curr. Biol. 8, 121-4
5. Ubc9p is the conjugating enzyme for the ubiquitin-like protein Smt3p. J. Biol. Chem. 272, 26799-802
6. Functional and phylogenetic analysis of the ubiquitylation system in Caenorhabditis elegans: ubiquitin-conjugating enzymes, ubiquitin-activating enzymes, and ubiquitin-like proteins. Genome Biol. 3, RESEARCH0002