The small ubiquitin-like modifier-1 (SUMO-1) consensus sequence mediates Ubc9 binding and is essential for SUMO-1 modification.
SUMO-1 is an ubiquitin-related protein that is covalently conjugated to a diverse assortment of proteins. The consequences of SUMO-1 modification include the regulation of protein-protein interactions, protein-DNA interactions, and protein subcellular localization. At present, very little is understood about the specific mechanisms that govern the recognition of proteins as substrates for SUMO-1 modification. However, many of the proteins that are modified by SUMO-1 interact directly with the SUMO-1 conjugating enzyme, Ubc9. These interactions suggest that Ubc9 binding may play an important role in substrate recognition as well as in substrate modification. The SUMO-1 consensus sequence (SUMO-1-CS) is a motif of conserved residues surrounding the modified lysine residue of most SUMO-1 substrates. This motif conforms to the sequence "PsiKXE," where Psi is a large hydrophobic residue, K is the lysine to which SUMO-1 is conjugated, X is any amino acid, and E is glutamic acid. In this study, we demonstrate that the SUMO-1-CS is a major determinant of Ubc9 binding and SUMO-1 modification. Mutating residues in the SUMO-1-CS abolishes both Ubc9 binding and substrate modification. These findings have important implications for how SUMO-1 substrates are recognized and for how SUMO-1 is ultimately transferred to specific lysine residues on these substrates.
Johns Hopkins University, School of Hygiene and Public Health, Department of Biochemistry and Molecular Biology, Baltimore, Maryland 21205, USA.
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Sampson
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Wang
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MJ
Matunis
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D016384:Consensus Sequence; D017124:Conserved Sequence; D018076:DNA, Complementary; D006801:Humans; D008025:Ligases / Q000737:chemistry / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D010957:Plasmids; D011485:Protein Binding; D014176:Protein Biosynthesis; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012156:Reticulocytes / Q000378:metabolism; D025842:SUMO-1 Protein; D016415:Sequence Alignment; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D044763:Ubiquitin-Conjugating Enzymes; D014452:Ubiquitins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000098843:Ubiquitin-Conjugating Enzyme UBC9
D018076:DNA, Complementary; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D025842:SUMO-1 Protein; D014452:Ubiquitins; D044763:Ubiquitin-Conjugating Enzymes; D008025:Ligases; D000098843:Ubiquitin-Conjugating Enzyme UBC9