title: Evidence for a sorting endosome in Arabidopsis root cells.
abstract: In eukaryotic cells, the endocytic and secretory pathways are key players in several physiological processes. These pathways are largely inter-connected in animal and yeast cells through organelles named sorting endosomes. Sorting endosomes are multi-vesicular compartments that redirect proteins towards various destinations, such as the lysosomes or vacuoles for degradation, the trans-Golgi network for retrograde transport and the plasma membrane for recycling. In contrast, cross-talk between the endocytic and secretory pathways has not been clearly established in plants, especially in terms of cargo protein trafficking. Here we show by co-localization analyses that endosomes labelled with the AtSORTING NEXIN1 (AtSNX1) protein overlap with the pre-vacuolar compartment in Arabidopsis root cells. In addition, alteration of the routing functions of AtSNX1 endosomes by drug treatments leads to mis-routing of endocytic and secretory cargo proteins. Based on these results, we propose that the AtSNX1 endosomal compartment represents a sorting endosome in root cells, and that this specialized organelle is conserved throughout eukaryotes.
authors.affiliation: Reproduction et Développement des Plantes, Institut Fédératif de Recherche 128, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université Claude Bernard Lyon I, Ecole Normale Supérieure de Lyon, France.
authors.forename: Yvon
authors.initials: Y
authors.lastname: Jaillais
authors.forename: Isabelle
authors.initials: I
authors.lastname: Fobis-Loisy
authors.forename: Christine
authors.initials: C
authors.lastname: Miège
authors.forename: Thierry
authors.initials: T
authors.lastname: Gaude
mesh_terms: D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D022162:Cytoplasmic Vesicles / Q000502:physiology; D004705:Endocytosis; D011992:Endosomes / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism*; D018517:Plant Roots / Q000502:physiology* / Q000648:ultrastructure; D021381:Protein Transport / Q000502:physiology; D033921:Vesicular Transport Proteins / Q000378:metabolism*; D021601:trans-Golgi Network / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D008565:Membrane Proteins; D033921:Vesicular Transport Proteins