title: FLI-1 functionally interacts with PIASxalpha, a member of the PIAS E3 SUMO ligase family.
abstract: 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.
authors.affiliation: Institut Curie, CNRS UMR 146, Orsay, France.
authors.forename: Emile
authors.initials: E
authors.lastname: van den Akker
authors.forename: Sabine
authors.initials: S
authors.lastname: Ano
authors.forename: Hsiu-Ming
authors.initials: HM
authors.lastname: Shih
authors.forename: Ling-Chi
authors.initials: LC
authors.lastname: Wang
authors.forename: Martine
authors.initials: M
authors.lastname: Pironin
authors.forename: Jorma J
authors.initials: JJ
authors.lastname: Palvimo
authors.forename: Noora
authors.initials: N
authors.lastname: Kotaja
authors.forename: Olivier
authors.initials: O
authors.lastname: Kirsh
authors.forename: Anne
authors.initials: A
authors.lastname: Dejean
authors.forename: Jacques
authors.initials: J
authors.lastname: Ghysdael
mesh_terms: 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
chemical_list: 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