Abstract
Sumoylation of p53 by the ubiquitin-like protein, SUMO-1/sentrin/PIC1, has been shown to stimulate its transcriptional activation activity. The SUMO E3 ligase, a key enzyme in the recognition of substrates to be sumoylated, has not yet been identified. We isolated PIAS1 (protein inhibitor of activated STAT1) as a SUMO-1 binding protein by yeast two-hybrid screening. In addition, PIAS1 bound p53 and Ubc9, the E2 for SUMO. PIAS1 that was mutated in the RING finger-like domain bound p53 and SUMO-1, but not Ubc9. PIAS1 catalyzed the sumoylation of p53 both in U2OS cells and in vitro in a domain-dependent manner. These data suggest that PIAS1 functions as a SUMO ligase, or possibly as a tightly bound regulator of it, toward p53.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Cell Fractionation
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Cell Line
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Genes, Reporter / genetics
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Humans
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Immunoblotting
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Ligases / metabolism
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Molecular Sequence Data
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Protein Binding
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Protein Inhibitors of Activated STAT
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Protein Structure, Tertiary
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Proteins / chemistry
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Proteins / metabolism*
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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SUMO-1 Protein
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Saccharomyces cerevisiae / physiology
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Sequence Alignment
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Tumor Suppressor Protein p53 / genetics
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Tumor Suppressor Protein p53 / metabolism*
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Two-Hybrid System Techniques
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Ubiquitin-Conjugating Enzymes*
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Ubiquitins / metabolism*
Substances
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Protein Inhibitors of Activated STAT
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Proteins
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Recombinant Fusion Proteins
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SUMO-1 Protein
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Tumor Suppressor Protein p53
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Ubiquitins
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Ubiquitin-Conjugating Enzymes
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Ligases
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ubiquitin-conjugating enzyme UBC9