title: Endocytic and secretory traffic in Arabidopsis merge in the trans-Golgi network/early endosome, an independent and highly dynamic organelle.
abstract: Plants constantly adjust their repertoire of plasma membrane proteins that mediates transduction of environmental and developmental signals as well as transport of ions, nutrients, and hormones. The importance of regulated secretory and endocytic trafficking is becoming increasingly clear; however, our knowledge of the compartments and molecular machinery involved is still fragmentary. We used immunogold electron microscopy and confocal laser scanning microscopy to trace the route of cargo molecules, including the BRASSINOSTEROID INSENSITIVE1 receptor and the REQUIRES HIGH BORON1 boron exporter, throughout the plant endomembrane system. Our results provide evidence that both endocytic and secretory cargo pass through the trans-Golgi network/early endosome (TGN/EE) and demonstrate that cargo in late endosomes/multivesicular bodies is destined for vacuolar degradation. Moreover, using spinning disc microscopy, we show that TGN/EEs move independently and are only transiently associated with an individual Golgi stack.
authors.affiliation: Department of Cell Biology, Heidelberg Institute for Plant Sciences, University of Heidelberg, 69120 Heidelberg, Germany.
authors.forename: Corrado
authors.initials: C
authors.lastname: Viotti
authors.forename: Julia
authors.initials: J
authors.lastname: Bubeck
authors.forename: York-Dieter
authors.initials: YD
authors.lastname: Stierhof
authors.forename: Melanie
authors.initials: M
authors.lastname: Krebs
authors.forename: Markus
authors.initials: M
authors.lastname: Langhans
authors.forename: Willy
authors.initials: W
authors.lastname: van den Berg
authors.forename: Walter
authors.initials: W
authors.lastname: van Dongen
authors.forename: Sandra
authors.initials: S
authors.lastname: Richter
authors.forename: Niko
authors.initials: N
authors.lastname: Geldner
authors.forename: Junpei
authors.initials: J
authors.lastname: Takano
authors.forename: Gerd
authors.initials: G
authors.lastname: Jürgens
authors.forename: Sacco C
authors.initials: SC
authors.lastname: de Vries
authors.forename: David G
authors.initials: DG
authors.lastname: Robinson
authors.forename: Karin
authors.initials: K
authors.lastname: Schumacher
mesh_terms: D017920:Antiporters / Q000378:metabolism; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism; D004705:Endocytosis; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D057146:Multivesicular Bodies / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D021381:Protein Transport; D021601:trans-Golgi Network / Q000378:metabolism*
chemical_list: D017920:Antiporters; D029681:Arabidopsis Proteins; C469216:BOR1 protein, Arabidopsis; D011494:Protein Kinases; C108270:BRI1 protein, Arabidopsis