The BioGRID | PUBLICATION VIEW

	Mol. Cell Aug (2008); 31(3):371-82
Ubc9 sumoylation regulates SUMO target discrimination-
Knipscheer P, Flotho A, Klug H, Olsen JV, van Dijk WJ, Fish A, Johnson ES, Mann M, Sixma TK, Pichler A
The Netherlands Cancer Institute and Center for Biomedical Genetics, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands-
Abstract: Posttranslational modification with small ubiquitin-related modifier, SUMO, is a widespread mechanism for rapid and reversible changes in protein function- Considering the large number of known targets, the number of enzymes involved in modification seems surprisingly low- a single E1, a single E2, and a few distinct E3 ligases- Here we show that autosumoylation of the mammalian E2-conjugating enzyme Ubc9 at Lys14 regulates target discrimination- While not altering its activity toward HDAC4, E2-25K, PML, or TDG, sumoylation of Ubc9 impairs its activity on RanGAP1 and strongly activates sumoylation of the transcriptional regulator Sp100- Enhancement depends on a SUMO-interacting motif -SIM- in Sp100 that creates an additional interface with the SUMO conjugated to the E2, a mechanism distinct from Ubc9 approximately SUMO thioester recruitment- The crystal structure of sumoylated Ubc9 demonstrates how the newly created binding interface can provide a gain in affinity otherwise provided by E3 ligases-
[PUBMED: 18691969]