title: The AP-1 μ adaptin is required for KNOLLE localization at the cell plate to mediate cytokinesis in Arabidopsis.
abstract: Formation of clathrin-coated vesicles (CCVs) requires the scaffolding adaptor protein (AP) complexes, which are conserved across all eukaryotes. The Arabidopsis genome encodes five AP complexes (AP-1 to AP-5), and each complex consists of four subunits. In this study, we characterized the poorly defined AP-1 complex by using genetics, proteomics and live cell imaging. We showed that the AP-1 µ adaptin subunit (AP1M2) was localized to the trans-Golgi network (TGN) and interacted physically with the AP-1 subunits in Arabidopsis. During treatment with brefeldin A (BFA), the functional fluorophore-tagged AP1M2 relocated to the BFA compartment. The AP1M2 loss-of-function mutant ap1m2 displayed deleterious growth defects, which were particularly evident in the compromised cytokinesis that was revealed by the presence of cell wall stubs in multinucleate cells. Immunolocalization of the cytokinesis-specific syntaxin KNOLLE (KN) in ap1m2 showed that KN was mislocalized and aggregated around the division plane, while a secretory marker targeting to the cell plate remained unaffected. Taken together, we propose that the AP-1 complex is required for cell plate-targeted trafficking of KN in dividing plant cells, and that it has a common role in mediating plant and yeast/animal cytokinesis systems which are fundamentally different.
authors.affiliation: Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502 Japan.
authors.forename: Ooi-Kock
authors.initials: OK
authors.lastname: Teh
authors.forename: Yuki
authors.initials: Y
authors.lastname: Shimono
authors.forename: Makoto
authors.initials: M
authors.lastname: Shirakawa
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Fukao
authors.forename: Kentaro
authors.initials: K
authors.lastname: Tamura
authors.forename: Tomoo
authors.initials: T
authors.lastname: Shimada
authors.forename: Ikuko
authors.initials: I
authors.lastname: Hara-Nishimura
mesh_terms: D033961:Adaptor Protein Complex 1 / Q000737:chemistry / Q000378:metabolism*; D017360:Arabidopsis / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000378:metabolism*; D020126:Brefeldin A / Q000494:pharmacology; D048749:Cytokinesis / Q000187:drug effects; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004705:Endocytosis / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018942:Macrolides / Q000494:pharmacology; D013058:Mass Spectrometry; D009154:Mutation; D063245:Plant Development / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D050765:Qa-SNARE Proteins / Q000378:metabolism*; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D021601:trans-Golgi Network / Q000187:drug effects / Q000378:metabolism
chemical_list: C583122:AP1M2 protein, Arabidopsis; D033961:Adaptor Protein Complex 1; D029681:Arabidopsis Proteins; C097724:KNOLLE protein, Arabidopsis; D018942:Macrolides; D050765:Qa-SNARE Proteins; D049452:Green Fluorescent Proteins; D020126:Brefeldin A; C036978:concanamycin A; D004121:Dimethyl Sulfoxide
keywords: Adaptin; Adaptor protein complex; Arabidopsis thaliana; Cytokinesis; KNOLLE; Trans-Golgi network