Redistribution of membrane proteins between the Golgi apparatus and endoplasmic reticulum in plants is reversible and not dependent on cytoskeletal networks.
We have fused the signal anchor sequences of a rat sialyl transferase and a human galactosyl transferase along with the Arabidopsis homologue of the yeast HDEL receptor (AtERD2) to the jellyfish green fluorescent protein (GFP) and transiently expressed the chimeric genes in tobacco leaves. All constructs targeted the Golgi apparatus and co-expression with DsRed fusions along with immunolabelling of stably transformed BY2 cells indicated that the fusion proteins located all Golgi stacks. Exposure of tissue to brefeldin A (BFA) resulted in the reversible redistribution of ST-GFP into the endoplasmic reticulum. This effect occurred in the presence of a protein synthesis inhibitor and also in the absence of microtubules or actin filaments. Likewise, reformation of Golgi stacks on removal of BFA was not dependent on either protein synthesis or the cytoskeleton. These data suggest that ER to Golgi transport in the cell types observed does not require cytoskeletal-based mechanochemical motor systems. However, expression of an inhibitory mutant of Arabidopsis Rab 1b (AtRab1b(N121I) significantly slowed down the recovery of Golgi fluorescence in BFA treated cells indicating a role for Rab1 in regulating ER to Golgi anterograde transport.
Saint-Jore
Claude M
CM
School of Biological and Molecular Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, UK.
Evins
Janet
J
Batoko
Henri
H
Brandizzi
Federica
F
Moore
Ian
I
Hawes
Chris
C
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D020126:Brefeldin A / Q000494:pharmacology; D002460:Cell Line; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects; D006056:Golgi Apparatus / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D018613:Microscopy, Confocal; D019441:Plant Epidermis / Q000166:cytology / Q000378:metabolism; D018515:Plant Leaves / Q000166:cytology / Q000378:metabolism; D030821:Plants, Genetically Modified; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012231:Rhizobium / Q000235:genetics; D014026:Nicotiana / Q000166:cytology / Q000378:metabolism*; D020761:rab1 GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism
D008164:Luminescent Proteins; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D020126:Brefeldin A; D003513:Cycloheximide; D020761:rab1 GTP-Binding Proteins