title: Terminal adenosyl transferase activity of posttranscriptional regulator HuR revealed by confocal on-bead screening.
abstract: Posttranscriptional regulation and RNA metabolism have become central topics in the understanding of mammalian gene expression and cell signalling, with the 3' untranslated region emerging as the coordinating unit. The 3' untranslated region trans-acting factor Hu protein R (HuR) forms a central posttranscriptional pathway node bridging between AU-rich element-mediated processes and microRNA regulation. While (m)RNA control by HuR has been extensively characterized, the molecular mode of action still remains elusive. Here we describe the identification of the first RRM3 (RNA recognition motif 3) targeted low molecular weight HuR inhibitors from a one-bead-one-compound library screen using confocal nanoscanning. A further compound characterization revealed the presence of an ATP-binding pocket within HuR RRM3, associated with enzymatic activity. Centered around a metal-ion-coordinating DxD motif, the catalytic site mediates 3'-terminal adenosyl modification of non-polyadenylated RNA substrates by HuR. These findings suggest that HuR actively contributes to RNA modification and maturation and thereby shed an entirely new light on the role of HuR in RNA metabolism.
authors.affiliation: Novartis Institutes for BioMedical Research, Basel, Switzerland. nicole-claudia.meisner@novartis.com
authors.forename: Nicole-Claudia
authors.initials: NC
authors.lastname: Meisner
authors.forename: Martin
authors.initials: M
authors.lastname: Hintersteiner
authors.forename: Jan-Marcus
authors.initials: JM
authors.lastname: Seifert
authors.forename: Roman
authors.initials: R
authors.lastname: Bauer
authors.forename: Roger Marc
authors.initials: RM
authors.lastname: Benoit
authors.forename: Armin
authors.initials: A
authors.lastname: Widmer
authors.forename: Torsten
authors.initials: T
authors.lastname: Schindler
authors.forename: Volker
authors.initials: V
authors.lastname: Uhl
authors.forename: Michaela
authors.initials: M
authors.lastname: Lang
authors.forename: Hubert
authors.initials: H
authors.lastname: Gstach
authors.forename: Manfred
authors.initials: M
authors.lastname: Auer
mesh_terms: D000954:Antigens, Surface / Q000378:metabolism*; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D006801:Humans; D008670:Metals / Q000378:metabolism; D008958:Models, Molecular; D017434:Protein Structure, Tertiary; D012316:RNA Nucleotidyltransferases / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*
chemical_list: D000954:Antigens, Surface; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; D008670:Metals; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012316:RNA Nucleotidyltransferases