Covalent modification of p73alpha by SUMO-1. Two-hybrid screening with p73 identifies novel SUMO-1-interacting proteins and a SUMO-1 interaction motif.
Two-hybrid screening in yeast with p73alpha isolated SUMO-1 (small ubiquitin-like modifier 1), the enzyme responsible for its conjugation, Ubc-9, and a number of novel SUMO-1-interacting proteins, including thymine DNA glycosylase, PM-Scl75, PIASx, PKY, and CHD3/ZFH. A subset of these proteins contain a common motif, hhXSXS/Taaa, where h is a hydrophobic ... amino acid and a is an acidic amino acid, that is shown to interact with SUMO-1 in the two-hybrid system. We show here that p73alpha, but not p73beta, can be covalently modified by SUMO-1. The major SUMO-1-modified residue in p73alpha is the C-terminal lysine (Lys(627)). The sequence surrounding this lysine conforms to a consensus SUMO-1 modification site b(X)XXhKXE, where b is a basic amino acid. SUMO-1-modified p73 is more rapidly degraded by the proteasome than unmodified p73, although SUMO-1 modification is not required for p73 degradation. SUMO-1 modification does not affect the transcriptional activity of p73alpha on an RGC-luciferase reporter gene in SK-N-AS cells. Instead, SUMO-1 modification may alter the subcellular localization of p73, because SUMO-1-modified p73 is preferentially found in detergent-insoluble fractions. Alternatively, it may modulate the interaction of p73 with other proteins that are substrates for SUMO-1 modification or which interact with SUMO-1, such as those identified here.
Mesh Terms:
Amino Acid Motifs, Amino Acid Sequence, Animals, Cell Line, Conserved Sequence, Cysteine Endopeptidases, Cysteine Proteinase Inhibitors, DNA-Binding Proteins, Gene Expression Regulation, Genes, Reporter, Genes, Tumor Suppressor, Humans, Leupeptins, Lysine, Molecular Sequence Data, Multienzyme Complexes, Nuclear Proteins, Proteasome Endopeptidase Complex, Protein Binding, Protein Processing, Post-Translational, Protein Transport, SUMO-1 Protein, Transfection, Tumor Cells, Cultured, Tumor Suppressor Protein p53, Tumor Suppressor Proteins, Two-Hybrid System Techniques, Ubiquitins
Amino Acid Motifs, Amino Acid Sequence, Animals, Cell Line, Conserved Sequence, Cysteine Endopeptidases, Cysteine Proteinase Inhibitors, DNA-Binding Proteins, Gene Expression Regulation, Genes, Reporter, Genes, Tumor Suppressor, Humans, Leupeptins, Lysine, Molecular Sequence Data, Multienzyme Complexes, Nuclear Proteins, Proteasome Endopeptidase Complex, Protein Binding, Protein Processing, Post-Translational, Protein Transport, SUMO-1 Protein, Transfection, Tumor Cells, Cultured, Tumor Suppressor Protein p53, Tumor Suppressor Proteins, Two-Hybrid System Techniques, Ubiquitins
J. Biol. Chem.
Date: Nov. 17, 2000
PubMed ID: 10961991
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