title: The intrinsically disordered C-terminal region of Arabidopsis thaliana TCP8 transcription factor acts both as a transactivation and self-assembly domain.
abstract: TCPs are plant specific transcription factors with non-canonical basic helix-loop-helix domains. While Arabidopsis thaliana has 24 TCPs involved in cell proliferation and differentiation, their mode of action has not been fully elucidated. Using bioinformatic tools, we demonstrate that TCP transcription factors belong to the intrinsically disordered proteins (IDP) family and that disorder is higher in class I TCPs than in class II TCPs. In particular, using bioinformatic and biochemical approaches, we have characterized TCP8, a class I TCP. TCP8 exhibits three intrinsically disordered regions (IDR) made of more than 50 consecutive residues, in which phosphorylable Ser residues are mainly clustered. Phosphorylation of Ser-211 that belongs to the central IDR was confirmed by mass spectrometry. Yeast two-hybrid assays also showed that the C-terminal IDR corresponds to a transactivation domain. Moreover, biochemical experiments demonstrated that TCP8 tends to oligomerize in dimers, trimers and higher-order multimers. Bimolecular fluorescence complementation (BiFC) experiments carried out on a truncated form of TCP8 lacking the C-terminal IDR indicated that it is effectively required for the pronounced self-assembly of TCP8. These data were reinforced by the prediction of a coiled coil domain in this IDR. The C-terminal IDR acts thus as an oligomerization domain and also a transactivation domain. Moreover, many Molecular Recognition Features (MoRFs) were predicted, indicating that TCP8 could interact with several partners to fulfill a fine regulation of transcription in response to various stimuli.
authors.affiliation: Université Pierre et Marie Curie, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, Unité de Recherche 5 - Equipe d'Accueil 7180 du Centre National de la Recherche Scientifique, case 156, 4 place Jussieu, 75252 Paris cedex 05, France.
authors.forename: Isabel
authors.initials: I
authors.lastname: Valsecchi
authors.forename: Emilie
authors.initials: E
authors.lastname: Guittard-Crilat
authors.forename: Régis
authors.initials: R
authors.lastname: Maldiney
authors.forename: Yvette
authors.initials: Y
authors.lastname: Habricot
authors.forename: Sabrina
authors.initials: S
authors.lastname: Lignon
authors.forename: Régine
authors.initials: R
authors.lastname: Lebrun
authors.forename: Emile
authors.initials: E
authors.lastname: Miginiac
authors.forename: Eric
authors.initials: E
authors.lastname: Ruelland
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Jeannette
authors.forename: Sandrine
authors.initials: S
authors.lastname: Lebreton
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D017360:Arabidopsis; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000378:metabolism; D064267:Intrinsically Disordered Proteins / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010766:Phosphorylation; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000596:Amino Acids; D029681:Arabidopsis Proteins; D064267:Intrinsically Disordered Proteins; D014157:Transcription Factors