title: Characterization of Arabidopsis Tubby-like proteins and redundant function of AtTLP3 and AtTLP9 in plant response to ABA and osmotic stress.
abstract: Tubby and Tubby-like proteins (TLPs) play essential roles in the development and function of mammal neuronal cells. In addition to the conserved carboxyl (C)-terminal Tubby domain, which is required for their plasma membrane (PM) tethering, plant TLPs also possess an amino (N)-terminal F-box domain to interact with specific Arabidopsis Skp1-like (ASK) proteins as functional SCF-type E3 ligases. Here, we report the molecular characterization of Arabidopsis TLPs (AtTLPs). β-Glucuronidase staining showed overlapped but distinct expression patterns of AtTLPs in Arabidopsis. Yeast two-hybrid assays further revealed that AtTLP1, AtTLP3, AtTLP6, AtTLP7, AtTLP9, AtTLP10 and AtTLP11 all interacted with specific ASKs, but AtTLP2, AtTLP5 and AtTLP8 did not. Subcellular localization observations in both Arabidopsis protoplasts and tobacco pollen tubes indicated that all GFP-AtTLP fusion proteins, except GFP-AtTLP8 which lacks the conserved phosphatidylinositol 4,5-bisphosphate binding sites, were targeted to the PM. Detailed studies on AtTLP3 demonstrated that AtTLP3 is a PM-tethered PIP2 binding protein which functions redundantly with AtTLP9 in abscisic acid (ABA)- and osmotic stress-mediated seed germination. Our results suggest that AtTLPs possibly work in multiple physiological and developmental processes in Arabidopsis, and AtTLP3 is also involved in ABA signaling pathway like AtTLP9 during seed germination and early seedling growth.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Bao
authors.forename: Wei-Meng
authors.initials: WM
authors.lastname: Song
authors.forename: Yan-Li
authors.initials: YL
authors.lastname: Jin
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Jiang
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Bei
authors.initials: B
authors.lastname: Li
authors.forename: Wei-Jie
authors.initials: WJ
authors.lastname: Huang
authors.forename: Hua
authors.initials: H
authors.lastname: Liu
authors.forename: Hong-Xia
authors.initials: HX
authors.lastname: Zhang
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D044783:F-Box Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D009154:Mutation; D009997:Osmotic Pressure; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000494:pharmacology; D030821:Plants, Genetically Modified; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D044783:F-Box Proteins; D010937:Plant Growth Regulators; D020033:Protein Isoforms; C513944:TLP9 protein, Arabidopsis; C000593815:Tubby-like F-box protein 3, Arabidopsis; D049452:Green Fluorescent Proteins; D000040:Abscisic Acid; D005966:Glucuronidase