title: Synergy of aromatic residues and phosphoserines within the intrinsically disordered DNA-binding inhibitory elements of the Ets-1 transcription factor.
abstract: The E26 transformation-specific (Ets-1) transcription factor is autoinhibited by a conformationally disordered serine-rich region (SRR) that transiently interacts with its DNA-binding ETS domain. In response to calcium signaling, autoinhibition is reinforced by calmodulin-dependent kinase II phosphorylation of serines within the SRR. Using mutagenesis and quantitative DNA-binding measurements, we demonstrate that phosphorylation-enhanced autoinhibition requires the presence of phenylalanine or tyrosine (ϕ) residues adjacent to the SRR phosphoacceptor serines. The introduction of additional phosphorylated Ser-ϕ-Asp, but not Ser-Ala-Asp, repeats within the SRR dramatically reinforces autoinhibition. NMR spectroscopic studies of phosphorylated and mutated SRR variants, both within their native context and as separate trans-acting peptides, confirmed that the aromatic residues and phosphoserines contribute to the formation of a dynamic complex with the ETS domain. Complementary NMR studies also identified the SRR-interacting surface of the ETS domain, which encompasses its positively charged DNA-recognition interface and an adjacent region of neutral polar and nonpolar residues. Collectively, these studies highlight the role of aromatic residues and their synergy with phosphoserines in an intrinsically disordered regulatory sequence that integrates cellular signaling and gene expression.
authors.affiliation: Department of Biochemistry and Molecular Biology, Department of Chemistry, and Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada V6T 1Z3;
authors.forename: Geneviève
authors.initials: G
authors.lastname: Desjardins
authors.affiliation: Department of Oncological Sciences, University of Utah School of Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112; and.
authors.forename: Charles A
authors.initials: CA
authors.lastname: Meeker
authors.affiliation: Department of Oncological Sciences, University of Utah School of Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112; and.
authors.forename: Niraja
authors.initials: N
authors.lastname: Bhachech
authors.affiliation: Department of Oncological Sciences, University of Utah School of Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112; and.
authors.forename: Simon L
authors.initials: SL
authors.lastname: Currie
authors.affiliation: Department of Biochemistry and Molecular Biology, Department of Chemistry, and Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada V6T 1Z3;
authors.forename: Mark
authors.initials: M
authors.lastname: Okon
authors.affiliation: Department of Oncological Sciences, University of Utah School of Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112; andHoward Hughes Medical Institute, Chevy Chase, MD 20815 barbara.graves@hci.utah.edu mcintosh@chem.ubc.ca.
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Graves
authors.affiliation: Department of Biochemistry and Molecular Biology, Department of Chemistry, and Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada V6T 1Z3; barbara.graves@hci.utah.edu mcintosh@chem.ubc.ca.
authors.forename: Lawrence P
authors.initials: LP
authors.lastname: McIntosh
mesh_terms: D006801:Humans; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides; D010768:Phosphoserine / Q000737:chemistry* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D050784:Proto-Oncogene Protein c-ets-1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid
chemical_list: C494041:ETS1 protein, human; D010455:Peptides; D050784:Proto-Oncogene Protein c-ets-1; D010768:Phosphoserine
keywords: fuzz complex; intrinsically disordered region; protein dynamics; transcription factor regulation