title: Quantitative phosphoproteomic analysis of early alterations in protein phosphorylation by 2,3,7,8-tetrachlorodibenzo-p-dioxin.
abstract: A comprehensive quantitative analysis of changes in protein phosphorylation preceding or accompanying transcriptional activation by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in 5L rat hepatoma cells was performed using the SILAC approach. Following exposure of the cells to DMSO or 1 nM TCDD for 0.5 to 2 h, 5648 phosphorylated peptides corresponding to 2156 phosphoproteins were identified. Eight peptides exhibited a statistically significantly altered phosphorylation because of TCDD exposure and 22 showed a regulation factor of ≥ 1.5 in one of the experiments per time point. The vast majority of the TCCD-induced phosphorylation changes had not been reported before. The transcription factor ARNT, the obligate partner for gene activation by the TCDD-bound Ah receptor, exhibited an up-regulation of its Ser77 phosphorylation, a modification known to control the differential binding of ARNT homodimers and heterodimers to different enhancers suggesting that this phosphorylation represents a novel mechanism contributing to the alteration of gene expression by TCDD. Other proteins with altered phosphorylation included, among others, various transcriptional coregulators previously unknown to participate in TCDD-induced gene activation, regulators of small GTPases of the Ras superfamily, UBX domain-containing proteins and the oncogenic protein LYRIC. The results open up new directions for research on the molecular mechanisms of dioxin action and toxicity.
authors.affiliation: Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: Schulz
authors.forename: Stefanie
authors.initials: S
authors.lastname: Brandner
authors.forename: Carola
authors.initials: C
authors.lastname: Eberhagen
authors.forename: Friederike
authors.initials: F
authors.lastname: Eckardt-Schupp
authors.forename: Martin R
authors.initials: MR
authors.lastname: Larsen
authors.forename: Ulrich
authors.initials: U
authors.lastname: Andrae
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D002853:Chromatography, Liquid; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics / Q000378:metabolism; D004785:Environmental Pollutants / Q000633:toxicity*; D005786:Gene Expression Regulation / Q000187:drug effects*; D007553:Isotope Labeling; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D020543:Proteome / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins; D051381:Rats; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics / Q000378:metabolism; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C497398:ARNT protein, rat; D002352:Carrier Proteins; D004785:Environmental Pollutants; D008565:Membrane Proteins; C493282:Mtdh protein, rat; D010750:Phosphoproteins; D000072317:Polychlorinated Dibenzodioxins; D020543:Proteome; D016601:RNA-Binding Proteins; D018336:Receptors, Aryl Hydrocarbon; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D019363:Cytochrome P-450 CYP1A1; D018631:ras Proteins