Topors acts as a SUMO-1 E3 ligase for p53 in vitro and in vivo

• Published in: FEBS letters Vol. 579; no. 22; pp. 5007 - 5012
• Main Authors: Weger, Stefan, Hammer, Eva, Heilbronn, Regine
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 12-09-2005
• Subjects: Carrier Proteins - genetics; Carrier Proteins - metabolism; DNA Topoisomerases, Type I - genetics; DNA Topoisomerases, Type I - metabolism; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; E3 ligase; GFP; glutathione S-transferase; green fluorescent protein; GST; HCMV; HeLa Cells; human cytomegalovirus; Humans; In Vitro Techniques; Neoplasm Proteins - genetics; Neoplasm Proteins - metabolism; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; p53; PIAS; Protein Binding; protein inhibitors of activated STAT; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; RING finger; Small ubiquitin-like modifier; SUMO; SUMO-1 Protein - genetics; SUMO-1 Protein - metabolism; Topors; Transcription Factors - genetics; Transcription Factors - metabolism; Tumor Suppressor Protein p53 - genetics; Tumor Suppressor Protein p53 - metabolism; UBC9; ubiquitin conjugating enzyme 9; Ubiquitin-Protein Ligases - genetics; Ubiquitin-Protein Ligases - metabolism; yellow fluorescent protein; YFP; Zinc Fingers; GFP; YFP; SUMO; E3 ligase; UBC9; HCMV; Small ubiquitin-like modifier; GST; RING finger; Topors; PIAS; p53
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/j.febslet.2005.07.088

Human Topors, which was originally identified as cellular binding partner of DNA topoisomerase I and of p53, has recently been shown to function as an ubiquitin E3 ligase for p53 in a manner dependent on its N′-terminally located RING finger. Here, we demonstrate that Topors also enhances the conjugation of the small ubiquitin-like modifier 1 (SUMO-1) to p53 in vivo and in a reconstituted in vitro system. The Topors SUMO-1 E3 ligase activity does not depend upon its RING finger motif. In HeLa cells, Topors induced p53 sumoylation was accompanied by an increase in endogenous p53 protein levels. Furthermore, Topors enhances the sumoylation of a variety of other, yet unidentified, cellular proteins.