title: Dynamic behavior of clathrin in Arabidopsis thaliana unveiled by live imaging.
abstract: Clathrin-coated vesicles (CCV) are necessary for selective transport events, including receptor-mediated endocytosis on the plasma membrane and cargo molecule sorting in the trans-Golgi network (TGN). Components involved in CCV formation include clathrin heavy and light chains and several adaptor proteins that are conserved among plants. Clathrin-dependent endocytosis has been shown to play an integral part in plant endocytosis. However, little information is known about clathrin dynamics in living plant cells. In this study, we have visualized clathrin in Arabidopsis thaliana by tagging clathrin light chain with green fluorescent protein (CLC-GFP). Quantitative evaluations of colocalization demonstrate that the majority of CLC-GFP is localized to the TGN, and a minor population is associated with multivesicular endosomes and the Golgi trans-cisternae. Live imaging further demonstrated the presence of highly dynamic clathrin-positive tubules and vesicles, which appeared to mediate interactions between the TGNs. CLC-GFP is also targeted to cell plates and the plasma membrane. Although CLC-GFP colocalizes with a dynamin isoform at the plasma membrane, these proteins exhibit distinct distributions at newly forming cell plates. This finding indicates independent functions of CLC (clathrin light chains) and dynamin during the formation of cell plates. We have also found that brefeldin A and wortmannin treatment causes distinctly different alterations in the dynamics and distribution of clathrin-coated domains at the plasma membrane. This could account for the different effects of these drugs on plant endocytosis.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Emi
authors.initials: E
authors.lastname: Ito
authors.forename: Masaru
authors.initials: M
authors.lastname: Fujimoto
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ebine
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Uemura
authors.forename: Takashi
authors.initials: T
authors.lastname: Ueda
authors.forename: Akihiko
authors.initials: A
authors.lastname: Nakano
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure*; D029681:Arabidopsis Proteins / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D020126:Brefeldin A / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D033941:Clathrin Light Chains / Q000378:metabolism*; D022163:Clathrin-Coated Vesicles / Q000187:drug effects / Q000378:metabolism*; D034281:Dynamins / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects; D011992:Endosomes / Q000378:metabolism; D008164:Luminescent Proteins; D018613:Microscopy, Confocal; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D030821:Plants, Genetically Modified; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011993:Recombinant Fusion Proteins; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D059008:Time-Lapse Imaging; D000077191:Wortmannin; D021601:trans-Golgi Network / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000730:Androstadienes; D029681:Arabidopsis Proteins; D033941:Clathrin Light Chains; D008164:Luminescent Proteins; D047428:Protein Kinase Inhibitors; D011500:Protein Synthesis Inhibitors; D011993:Recombinant Fusion Proteins; D020126:Brefeldin A; D034281:Dynamins; D000077191:Wortmannin