title: Luminescence detection of SNARE-SNARE interaction in Arabidopsis protoplasts.
abstract: Membrane associated proteins SNAREs (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptors) provide the minimal fusion machinery necessary for cellular vesicles to fuse to target organelle membranes in eukaryotic cells. Despite the conserved nature of the fusion machinery in all eukaryotes, it still remains challenging to identify functional SNARE pairs in higher plants. We developed a method based on a split-luciferase complementation assay for detecting changes in SNARE-SNARE interaction by luminescence within Arabidopsis protoplasts that express recombinant proteins at physiological levels in 96-well plates. The reliability of the assay was confirmed by three experiments. First, reduction of the SNARE-SNARE interaction caused by a single amino acid substitution adjacent to the SNARE motif in endosome-localized AtVAM3/SYP22 (syntaxin of plant 22) was detected by a reduction of luminescence. Second, reduction of the interaction between plasma-membrane localized SYP121 and VAMP722 in response to sodium azide was detected in real-time. Third, the results of 21 SNARE pairs investigated by this method largely agreed with the results from previously reported co-immunoprecipitation assays. Using the method, we newly identified the interaction between SYP121 and VAMP722 was significantly increased when the protoplasts were incubated in the light. Microscopic observation of transgenic Arabidopsis expressing GFP-SYP121 (green fluorescent protein tagged SYP121) from its own promoter suggested that the plasma-membrane localization of GFP-SYP121 is maintained by light. These suggested that the vesicle trafficking pathway mediated by SYP121 might be regulated by light in Arabidopsis. In general, this article demonstrated the method that can generate new biological insight of the SNARE protein interactions in plant cells.
authors.affiliation: Louisiana State University, 260 Life Sciences Building, Baton Rouge, LA 70803, USA. kato@LSU.edu
authors.forename: Naohiro
authors.initials: N
authors.lastname: Kato
authors.forename: Yukichi
authors.initials: Y
authors.lastname: Fujikawa
authors.forename: Taylor
authors.initials: T
authors.lastname: Fuselier
authors.forename: Rimanatou
authors.initials: R
authors.lastname: Adamou-Dodo
authors.forename: Aiko
authors.initials: A
authors.lastname: Nishitani
authors.forename: Masa H
authors.initials: MH
authors.lastname: Sato
mesh_terms: D019943:Amino Acid Substitution; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005816:Genetic Complementation Test; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008163:Luminescent Measurements; D052817:Phototrophic Processes; D030821:Plants, Genetically Modified; D054730:Protein Interaction Domains and Motifs; D011523:Protoplasts / Q000378:metabolism; D050765:Qa-SNARE Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D050766:Qb-SNARE Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D050600:SNARE Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C479425:PEN1 protein, Arabidopsis; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D011993:Recombinant Fusion Proteins; D050600:SNARE Proteins; C472135:SYP61 protein, Arabidopsis; C108430:Vam3 protein, Arabidopsis; C120751:vesicle transport v-SNARE 11 protein, Arabidopsis; D049452:Green Fluorescent Proteins