Endocytic and secretory traffic in Arabidopsis merge in the trans-Golgi network/early endosome, an independent and highly dynamic organelle.
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.
Viotti
Corrado
C
Department of Cell Biology, Heidelberg Institute for Plant Sciences, University of Heidelberg, 69120 Heidelberg, Germany.
Bubeck
Julia
J
Stierhof
York-Dieter
YD
Krebs
Melanie
M
Langhans
Markus
M
van den Berg
Willy
W
van Dongen
Walter
W
Richter
Sandra
S
Geldner
Niko
N
Takano
Junpei
J
Jürgens
Gerd
G
de Vries
Sacco C
SC
Robinson
David G
DG
Schumacher
Karin
K
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*
D017920:Antiporters; D029681:Arabidopsis Proteins; C469216:BOR1 protein, Arabidopsis; D011494:Protein Kinases; C108270:BRI1 protein, Arabidopsis