title: The subcellular localization of Tubby-like proteins and participation in stress signaling and root colonization by the mutualist Piriformospora indica.
abstract: Tubby and Tubby-like proteins (TLPs) were first discovered in mammals, where they are involved in the development and function of neuronal cells. Due to their importance as plasma membrane (PM)-tethered transcription factors or mediators of vesicle trafficking, their lack causes obesity and other disease syndromes. Phosphatidylinositol 4,5-bisphosphate binding of the carboxyl-terminal Tubby domain attaches these proteins to the PM and vesicles and is essential for function. TLPs are conserved across eukaryotic kingdoms including plants, suggesting fundamental biological functions of TLPs. Plant TLPs possess an amino-terminal F-box domain that distinguishes them from other eukaryotic TLPs. Arabidopsis (Arabidopsis thaliana) encodes 11 AtTLPs that fall into six phylogenetic clades. We identified the significance of AtTLPs for root colonization of Arabidopsis by the mutualistic fungus Piriformospora indica. Our results further indicate conserved phosphatidylinositol 4,5-bisphosphate-binding sites in the Tubby domains that are required for PM anchoring of AtTLPs. More detailed studies revealed phospholipase C-triggered release of AtTLP3 from the PM, indicating a conserved mechanism as reported for mammalian Tubby and TLP3. We further show that hydrogen peroxide stimulates the release of AtTLP3 from the PM, presumably for activating downstream events. Different from mammalian homologs, the amino-terminal part of almost all AtTLPs has nucleocytosolic and plastidial localization patterns. Thus, it is tempting to assume that TLPs translate reactive oxygen species currents into signaling not only for transcriptional regulation in the nucleus but also affect plastid-associated functions after release from the PM.
authors: Institute of Phytopathology and Applied Zoology, Research Centre for Biosystems, Land Use, and Nutrition, Justus Liebig University, D-35392 Giessen, Germany.
authors: Marco Uwe
authors: MU
authors: Reitz
authors: Jeff Kweku
authors: JK
authors: Bissue
authors: Kathleen
authors: K
authors: Zocher
authors: Agnès
authors: A
authors: Attard
authors: Ralph
authors: R
authors: Hückelhoven
authors: Katja
authors: K
authors: Becker
authors: Jafargholi
authors: J
authors: Imani
authors: Ruth
authors: R
authors: Eichmann
authors: Patrick
authors: P
authors: Schäfer
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001487:Basidiomycota / Q000254:growth & development*; D001665:Binding Sites; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D044783:F-Box Proteins / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D018517:Plant Roots / Q000378:metabolism / Q000382:microbiology*; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology; D018087:Plastids / Q000378:metabolism; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological; D013559:Symbiosis; D014170:Transformation, Genetic; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D044783:F-Box Proteins; D011993:Recombinant Fusion Proteins; D006861:Hydrogen Peroxide; D010738:Type C Phospholipases