Structural basis for E2-mediated SUMO conjugation revealed by a complex between ubiquitin-conjugating enzyme Ubc9 and RanGAP1.
E2 enzymes catalyze attachment of ubiquitin and ubiquitin-like proteins to lysine residues directly or through E3-mediated reactions. The small ubiquitin-like modifier SUMO regulates nuclear transport, stress response, and signal transduction in eukaryotes and is essential for cell-cycle progression in yeast. In contrast to most ubiquitin conjugation, the SUMO E2 enzyme Ubc9 is sufficient for substrate recognition and lysine modification of known SUMO targets. Crystallographic analysis of a complex between mammalian Ubc9 and a C-terminal domain of RanGAP1 at 2.5 A reveals structural determinants for recognition of consensus SUMO modification sequences found within SUMO-conjugated proteins. Structure-based mutagenesis and biochemical analysis of Ubc9 and RanGAP1 reveal distinct motifs required for substrate binding and SUMO modification of p53, IkappaBalpha, and RanGAP1.
Bernier-Villamor
Victor
V
Biochemistry Department, Structural Biology Program, Weill Medical College of Cornell University, New York, NY 10021, USA.
Sampson
Deborah A
DA
Matunis
Michael J
MJ
Lima
Christopher D
CD
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D020690:GTPase-Activating Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008025:Ligases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D025842:SUMO-1 Protein / Q000737:chemistry* / Q000378:metabolism; D016415:Sequence Alignment; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D044763:Ubiquitin-Conjugating Enzymes; D000098843:Ubiquitin-Conjugating Enzyme UBC9
D020690:GTPase-Activating Proteins; C092317:RANGAP1 protein, human; D025842:SUMO-1 Protein; D044763:Ubiquitin-Conjugating Enzymes; D008025:Ligases; D000098843:Ubiquitin-Conjugating Enzyme UBC9