title: The cAMP pathway regulates mRNA decay through phosphorylation of the RNA-binding protein TIS11b/BRF1.
abstract: TPA-inducible sequence 11b/butyrate response factor 1 (TIS11b/BRF1) belongs to the tristetraprolin (TTP) family of zinc-finger proteins, which bind to mRNAs containing AU-rich elements in their 3'-untranslated region and target them for degradation. Regulation of TTP family function through phosphorylation by p38 MAP kinase and Akt/protein kinase B signaling pathways has been extensively studied. In contrast, the role of cAMP-dependent protein kinase (PKA) in the control of TTP family activity in mRNA decay remains largely unknown. Here we show that PKA activation induces TIS11b gene expression and protein phosphorylation. Site-directed mutagenesis combined with kinase assays and specific phosphosite immunodetection identified Ser-54 (S54) and Ser-334 (S334) as PKA target amino acids in vitro and in vivo. Phosphomimetic mutation of the C-terminal S334 markedly increased TIS11b half-life and, unexpectedly, enhanced TIS11b activity on mRNA decay. Examination of protein-protein interactions between TIS11b and components of the mRNA decay machinery revealed that mimicking phosphorylation at S334 enhances TIS11b interaction with the decapping coactivator Dcp1a, while preventing phosphorylation at S334 potentiates its interaction with the Ccr4-Not deadenylase complex subunit Cnot1. Collectively our findings establish for the first time that cAMP-elicited phosphorylation of TIS11b plays a key regulatory role in its mRNA decay-promoting function.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, INSERM U1036, Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biosciences et Biotechnologies de Grenoble, Laboratoire Biologie du Cancer et de l'Infection, and Université Grenoble Alpes, Unité Mixte de Recherche-S1036, F-38000 Grenoble, France.
authors.forename: Felicitas
authors.initials: F
authors.lastname: Rataj
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, INSERM U1036, Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biosciences et Biotechnologies de Grenoble, Laboratoire Biologie du Cancer et de l'Infection, and Université Grenoble Alpes, Unité Mixte de Recherche-S1036, F-38000 Grenoble, France.
authors.forename: Séverine
authors.initials: S
authors.lastname: Planel
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, INSERM U1036, Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biosciences et Biotechnologies de Grenoble, Laboratoire Biologie du Cancer et de l'Infection, and Université Grenoble Alpes, Unité Mixte de Recherche-S1036, F-38000 Grenoble, France.
authors.forename: Agnès
authors.initials: A
authors.lastname: Desroches-Castan
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, INSERM U1036, Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biosciences et Biotechnologies de Grenoble, Laboratoire Biologie du Cancer et de l'Infection, and Université Grenoble Alpes, Unité Mixte de Recherche-S1036, F-38000 Grenoble, France.
authors.forename: Juliette
authors.initials: J
authors.lastname: Le Douce
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, INSERM U1036, Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biosciences et Biotechnologies de Grenoble, Laboratoire Biologie du Cancer et de l'Infection, and Université Grenoble Alpes, Unité Mixte de Recherche-S1036, F-38000 Grenoble, France.
authors.forename: Khadija
authors.initials: K
authors.lastname: Lamribet
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, INSERM U1036, Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biosciences et Biotechnologies de Grenoble, Laboratoire Biologie du Cancer et de l'Infection, and Université Grenoble Alpes, Unité Mixte de Recherche-S1036, F-38000 Grenoble, France.
authors.forename: Josiane
authors.initials: J
authors.lastname: Denis
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, INSERM U1036, Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biosciences et Biotechnologies de Grenoble, Laboratoire Biologie du Cancer et de l'Infection, and Université Grenoble Alpes, Unité Mixte de Recherche-S1036, F-38000 Grenoble, France.
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Feige
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, INSERM U1036, Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biosciences et Biotechnologies de Grenoble, Laboratoire Biologie du Cancer et de l'Infection, and Université Grenoble Alpes, Unité Mixte de Recherche-S1036, F-38000 Grenoble, France nadia.cherradi@cea.fr.
authors.forename: Nadia
authors.initials: N
authors.lastname: Cherradi
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D019556:COS Cells; D018929:Cell Culture Techniques; D002522:Chlorocebus aethiops; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004722:Endoribonucleases / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D054730:Protein Interaction Domains and Motifs; D000067776:RNA Recognition Motif Proteins / Q000378:metabolism; D020871:RNA Stability / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D035381:TATA-Binding Protein Associated Factors / Q000235:genetics* / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism; D051816:Tristetraprolin / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; C441028:BRF1 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D000067776:RNA Recognition Motif Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D035381:TATA-Binding Protein Associated Factors; D015534:Trans-Activators; D051816:Tristetraprolin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D004722:Endoribonucleases; C466279:DCP1A protein, human