Involvement of PIAS1 in the sumoylation of tumor suppressor p53.

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.
Mesh Terms:
Amino Acid Sequence, Cell Fractionation, Cell Line, Genes, Reporter, Humans, Immunoblotting, Ligases, Molecular Sequence Data, Protein Binding, Protein Inhibitors of Activated STAT, Protein Structure, Tertiary, Proteins, Recombinant Fusion Proteins, SUMO-1 Protein, Saccharomyces cerevisiae, Sequence Alignment, Tumor Suppressor Protein p53, Two-Hybrid System Techniques, Ubiquitin-Conjugating Enzymes, Ubiquitins
Mol. Cell
Date: Sep. 01, 2001
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