FLI-1 functionally interacts with PIASxalpha, a member of the PIAS E3 SUMO ligase family.
FLI-1 is a transcription factor of the ETS family that is involved in several developmental processes and that becomes oncogenic when overexpressed or mutated. As the functional regulators of FLI-1 are largely unknown, we performed a yeast two-hybrid screen with FLI-1 and identified the SUMO E3 ligase PIASxalpha/ARIP3 as a novel in vitro and in vivo binding partner of FLI-1. This interaction involved the ETS domain of FLI-1 and required the integrity of the SAP domain of PIASxalpha/ARIP3. SUMO-1 and Ubc9, the ubiquitin carrier protein component in the sumoylation pathway, were also identified as interactors of FLI-1. Both PIASxalpha/ARIP3 and the closely related PIASxbeta isoform specifically enhanced sumoylation of FLI-1 at Lys(67), located in its N-terminal activation domain. PIASxalpha/ARIP3 relocalized the normally nuclear but diffusely distributed FLI-1 protein to PIASxalpha nuclear bodies and repressed FLI-1 transcriptional activation as assessed using different ETS-binding site-dependent promoters and different cell systems. PIASxalpha repressive activity was independent of sumoylation and did not result from inhibition of FLI-1 DNA-binding activity. Analysis of the properties of a series of ARIP3 mutants showed that the repressive properties of PIASxalpha/ARIP3 require its physical interaction with FLI-1, identifying PIASxalpha as a novel corepressor of FLI-1.
van den Akker
Emile
E
Institut Curie, CNRS UMR 146, Orsay, France.
Ano
Sabine
S
Shih
Hsiu-Ming
HM
Wang
Ling-Chi
LC
Pironin
Martine
M
Palvimo
Jorma J
JJ
Kotaja
Noora
N
Kirsh
Olivier
O
Dejean
Anne
A
Ghysdael
Jacques
J
D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008239:Lysine / Q000378:metabolism; D011485:Protein Binding; D050828:Protein Inhibitors of Activated STAT / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D051789:Proto-Oncogene Protein c-fli-1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D025842:SUMO-1 Protein / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D015533:Transcriptional Activation / Q000235:genetics; D020798:Two-Hybrid System Techniques; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism; D000098843:Ubiquitin-Conjugating Enzyme UBC9
C078433:FLI1 protein, human; C501001:PIAS2 protein, human; D050828:Protein Inhibitors of Activated STAT; D051789:Proto-Oncogene Protein c-fli-1; D012097:Repressor Proteins; D025842:SUMO-1 Protein; D004247:DNA; D044763:Ubiquitin-Conjugating Enzymes; D000098843:Ubiquitin-Conjugating Enzyme UBC9; D008239:Lysine