Repression of E1AF transcriptional activity by sumoylation and PIASy.
E1AF is a member of the Ets transcriptional factor family, and it plays a crucial role in tumor metastasis. However, the molecular mechanisms regulating its activity are not well characterized. In this study, we show that E1AF is sumoylated at four lysine residues, both in vivo and in vitro. Replacement of these lysines by arginine enhanced the transcriptional activity of E1AF, suggesting that sumoylation negatively regulates E1AF activity. We further demonstrated that PIASy enhanced sumoylation of E1AF as a specific SUMO-E3 ligase. In addition, PIASy repressed the transcriptional activity of both the wild-type and sumoylation defective mutants. However, the C342A mutant of PIASy, which abrogates SUMO-E3 ligase activity, had a significantly decreased ability to repress E1AF activity. Taken together, our results indicate that PIASy negatively regulates E1AF-mediated transcription by both E1AF sumoylation in a dependent and independent fashion.
Nishida
Tamotsu
T
Department of Human Functional Genomics, Life Science Research Center, Mie University, 1577 Kurima-machiya, Tsu 514-8507, Japan. nishida@gene.mie-u.ac.jp
Terashima
Motoko
M
Fukami
Kiyoko
K
Yamada
Yoshiji
Y
D017500:Adenovirus E1A Proteins / Q000235:genetics*; D006801:Humans; D000075223:Poly-ADP-Ribose Binding Proteins; D050828:Protein Inhibitors of Activated STAT / Q000235:genetics*; D011499:Protein Processing, Post-Translational / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D050783:Proto-Oncogene Proteins c-ets; D025842:SUMO-1 Protein / Q000235:genetics*; D015533:Transcriptional Activation / Q000235:genetics*; D025801:Ubiquitin / Q000235:genetics
D017500:Adenovirus E1A Proteins; C079853:ETV4 protein, human; C485891:PIAS4 protein, human; D000075223:Poly-ADP-Ribose Binding Proteins; D050828:Protein Inhibitors of Activated STAT; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D025842:SUMO-1 Protein; D025801:Ubiquitin