|Title||BEN3/BIG2 ARF GEF is involved in brefeldin a-sensitive trafficking at the trans-golgi network/early endosome in arabidopsis thaliana|
|Author(s)||Kitakura, Saeko; Adamowski, Maciek; Matsuura, Yuki; Santuari, Luca; Kouno, Hirotaka; Arima, Kohei; Hardtke, Christian S.; Friml, Jiř; Kakimoto, Tatsuo; Tanaka, Hirokazu|
|Source||Plant and Cell Physiology 58 (2017)10. - ISSN 0032-0781 - p. 1801 - 1811.|
Plant Developmental Biology
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||Arabidopsis - ARF GEF - Auxin - Brefeldin A - PIN-FORMED1 - Trans-Golgi network|
Membrane traffic at the trans-Golgi network (TGN) is crucial for correctly distributing various membrane proteins to their destination. Polarly localized auxin efflux proteins, including PIN-FORMED1 (PIN1), are dynamically transported between the endosomes and the plasma membrane (PM) in the plant cells. The intracellular trafficking of PIN1 protein is sensitive to the fungal toxin brefeldin A (BFA), which is known to inhibit guanine nucleotide exchange factors for ADP ribosylation factors (ARF GEFs) such as GNOM. However, the molecular details of the BFA-sensitive trafficking pathway have not been fully revealed. In a previous study, we identified an Arabidopsis mutant BFA-visualized endocytic trafficking defective 3 (ben3) which exhibited reduced sensitivity to BFA in terms of BFA-induced intracellular PIN1 agglomeration. Here, we show that BEN3 encodes a member of BIG family ARF GEFs, BIG2. BEN3/BIG2 tagged with fluorescent proteins co-localized with markers for the TGN/early endosome (EE). Inspection of conditionally induced de novo synthesized PIN1 confirmed that its secretion to the PM is BFA sensitive, and established BEN3/BIG2 as a crucial component of this BFA action at the level of the TGN/EE. Furthermore, ben3 mutation alleviated BFAinduced agglomeration of another TGN-localized ARF GEF, BEN1/MIN7. Taken together, our results suggest that BEN3/BIG2 is an ARF GEF component, which confers BFA sensitivity to the TGN/EE in Arabidopsis.