title: SUMOylation can regulate the activity of ETS-like transcription factor 4.
abstract: ETS-like transcription factor 4 (ELK4) (a.k.a. serum response factor accessory protein 1) belongs to the ternary complex factor (TCF) subfamily of E twenty-six (ETS) domain transcription factors. Compared to the other TCF subfamily members, ELK1 and ELK3 (NET), there is limited information of the mechanisms regulating the ELK4 activity. Here, we show that the ELK4 can be covalently modified (SUMOylated) by small ubiquitin-related modifier (SUMO) 1 protein, an important regulator of signaling and transcription. SUMOylation of ELK4 was reversed by SUMO-specific proteases (SENP) 1 and 2 and stimulated by SUMO E3 ligase PIAS3. Conserved lysine residue 167 that is located in the NET inhibitory domain of ELK4 was identified as the main site of SUMO-1 conjugation. Interestingly, mutation of the K167 disrupting the SUMOylation markedly enhanced the transcriptional activity of the ELK4, but weakened its repressive function on c-fos promoter. In conclusion, our results suggest that covalent modification by SUMO-1 can regulate the activity of ELK4, contributing to the transcriptional repression by the ELK4.
authors.affiliation: Institute of Biomedicine/Medical Biochemistry, University of Eastern Finland, Kuopio, FI-70211 Kuopio, Finland.
authors.forename: Sanna
authors.initials: S
authors.lastname: Kaikkonen
authors.forename: Harri
authors.initials: H
authors.lastname: Makkonen
authors.forename: Miia
authors.initials: M
authors.lastname: Rytinki
authors.forename: Jorma J
authors.initials: JJ
authors.lastname: Palvimo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D003546:Cysteine Endopeptidases / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D007124:Immunoenzyme Techniques; D018832:Molecular Chaperones / Q000378:metabolism; D008969:Molecular Sequence Data; D050828:Protein Inhibitors of Activated STAT / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D025842:SUMO-1 Protein / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D050808:ets-Domain Protein Elk-4 / Q000235:genetics* / Q000378:metabolism*
chemical_list: C494193:ELK4 protein, human; D018832:Molecular Chaperones; C484745:PIAS3 protein, human; D050828:Protein Inhibitors of Activated STAT; D025842:SUMO-1 Protein; D050808:ets-Domain Protein Elk-4; D010450:Endopeptidases; C404512:SENP1 protein, human; D003546:Cysteine Endopeptidases; C501833:SENP2 protein, human