title: RABA members act in distinct steps of subcellular trafficking of the FLAGELLIN SENSING2 receptor.
abstract: Cell surface proteins play critical roles in the perception of environmental stimuli at the plasma membrane (PM) and ensuing signal transduction. Intracellular localization of such proteins must be strictly regulated, which requires elaborate integration of exocytic and endocytic trafficking pathways. Subcellular localization of Arabidopsis thaliana FLAGELLIN SENSING2 (FLS2), a receptor that recognizes bacterial flagellin, also depends on membrane trafficking. However, our understanding about the mechanisms involved is still limited. In this study, we visualized ligand-induced endocytosis of FLS2 using green fluorescent protein (GFP)-tagged FLS2 expressed in Nicotiana benthamiana. Upon treatment with the flg22 peptide, internalized FLS2-GFP from the PM was transported to a compartment with properties intermediate between the trans-Golgi network (TGN) and the multivesicular endosome. This compartment gradually discarded the TGN characteristics as it continued along the trafficking pathway. We further found that FLS2 endocytosis involves distinct RABA/RAB11 subgroups at different steps. Moreover, we demonstrated that transport of de novo-synthesized FLS2 to the PM also involves a distinct RABA/RAB11 subgroup. Our results demonstrate the complex regulatory system for properly localizing FLS2 and functional differentiation in RABA members in endo- and exocytosis.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Seung-won
authors.initials: SW
authors.lastname: Choi
authors.forename: Takayuki
authors.initials: T
authors.lastname: Tamaki
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ebine
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Uemura
authors.forename: Takashi
authors.initials: T
authors.lastname: Ueda
authors.forename: Akihiko
authors.initials: A
authors.lastname: Nakano
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D004705:Endocytosis; D011992:Endosomes / Q000235:genetics / Q000378:metabolism; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008024:Ligands; D019441:Plant Epidermis / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D050765:Qa-SNARE Proteins / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D021601:trans-Golgi Network / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D008024:Ligands; D050765:Qa-SNARE Proteins; C472135:SYP61 protein, Arabidopsis; D049452:Green Fluorescent Proteins; D011494:Protein Kinases; C411853:FLS2 protein, Arabidopsis; C495672:Ara7 protein, Arabidopsis; C530073:VHA-a1 protein, Arabidopsis; D025262:Vacuolar Proton-Translocating ATPases; D020691:rab GTP-Binding Proteins