title: Structural characterization of a noncovalent complex between ubiquitin and the transactivation domain of the erythroid-specific factor EKLF.
abstract: Like other acidic transactivation domains (TAD), the minimal TAD from the erythroid-specific transcription factor EKLF (EKLFTAD) has been shown to contribute both to its transcriptional activity as well as to its ubiquitin(UBI)-mediated degradation. In this article, we examine the activation-degradation role of the acidic TAD of EKLF and demonstrate that the first 40 residues (EKLFTAD1) within this region form a noncovalent interaction with UBI. Nuclear magnetic resonance (NMR) structural studies of an EKLFTAD1-UBI complex show that EKLFTAD1 adopts a 14-residue α helix that forms the recognition interface with UBI in a similar manner as the UBI-interacting helix of Rabex5. We also identify a similar interaction between UBI and the activation-degradation region of SREBP1a, but not with the activation-degradation regions of p53, GAL4, and VP16. These results suggest that select activation-degradation regions like the ones found in EKLF and SREBP1a function in part through their ability to form noncovalent interactions with UBI.
authors.affiliation: Département de Biochimie, Université de Montréal, C.P. 6128 Succursale Centre-Ville, Montréal, QC H3C 3J7, Canada.
authors.forename: Luca
authors.initials: L
authors.lastname: Raiola
authors.forename: Mathieu
authors.initials: M
authors.lastname: Lussier-Price
authors.forename: David
authors.initials: D
authors.lastname: Gagnon
authors.forename: Julien
authors.initials: J
authors.lastname: Lafrance-Vanasse
authors.forename: Xavier
authors.initials: X
authors.lastname: Mascle
authors.forename: Genevieve
authors.initials: G
authors.lastname: Arseneault
authors.forename: Pascale
authors.initials: P
authors.lastname: Legault
authors.forename: Jacques
authors.initials: J
authors.lastname: Archambault
authors.forename: James G
authors.initials: JG
authors.lastname: Omichinski
mesh_terms: D019943:Amino Acid Substitution; D001665:Binding Sites; D002460:Cell Line; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D051741:Kruppel-Like Transcription Factors / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular; D054730:Protein Interaction Domains and Motifs; D055550:Protein Stability; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D025801:Ubiquitin / Q000737:chemistry* / Q000235:genetics
chemical_list: D051741:Kruppel-Like Transcription Factors; D025801:Ubiquitin; C080774:erythroid Kruppel-like factor