The N-myristoylated Rab-GTPase m-Rabmc is involved in post-Golgi trafficking events to the lytic vacuole in plant cells.
We report on the sub-cellular localisation and function of m-Rab(mc), a N-myristoylated plant-specific Rab-GTPase previously characterised at the molecular level and also by structural analysis in Mesembryanthemum crystallinum. By confocal laser scanning microscopy, we identified m-Rab(mc) predominantly on the prevacuolar compartment of the lytic vacuole but also on the Golgi apparatus in various plant cell types. Two complementary approaches were used immunocytochemistry and cyan fluorescent protein (CFP)/yellow fluorescent protein (YFP)-fusion proteins. Co-localisation studies of m-Rab(mc) with a salinity stress modulated integral calcium-ATPase suggest involvement of m-Rab(mc) in a plant-specific transport pathway to the prevacuolar compartment of the lytic vacuole. This hypothesis was strengthened by the inhibition of the transport of aleurain fused to green fluorescent protein (GFP), a marker of the lytic vacuole, in the presence of the dominant negative mutant m-Rab(mc)(N147I) in Arabidopsis thaliana protoplasts. The inhibitory effect of m-Rab(mc)(N147I) was specific for the transport pathway to the lytic vacuole, since the transport of chitinase-YFP, a marker for the neutral vacuole, was not hindered by the mutant.
Bolte
Susanne
S
Laboratoire de Dynamique de la Compartimentation Cellulaire, Institut des Sciences du Végétal, CNRS, UPR2355, Avenue de la Terrasse, Bâtiment 23-24, 91198 Gif-sur-Yvette Cedex, France. susanne.bolte@isv.cnrs-gif.fr
Brown
Spencer
S
Satiat-Jeunemaitre
Béatrice
B
D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D019677:Artificial Gene Fusion; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002688:Chitinases / Q000378:metabolism; D017343:Genes, Plant; D006056:Golgi Apparatus / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D035723:Mesembryanthemum / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology; D011523:Protoplasts / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D014617:Vacuoles / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
D008164:Luminescent Proteins; D010940:Plant Proteins; D011994:Recombinant Proteins; D049452:Green Fluorescent Proteins; D002688:Chitinases; D020691:rab GTP-Binding Proteins; D000252:Calcium-Transporting ATPases