BEN3/BIG2 ARF GEF is Involved in Brefeldin A-Sensitive Trafficking at the trans-Golgi Network/Early Endosome in Arabidopsis thaliana

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Authors	KITAKURA S. ADAMOWSKI M. MATSUURA Y. SANTUARI L. KOUNO H. ARIMA K. HARDTKE C.S. FRIML Jiří KAKIMOTO T. TANAKA H.
Year of publication	2017
Type	Article in Periodical
Magazine / Source	Plant and Cell Physiology
MU Faculty or unit	Central European Institute of Technology
Citation
Web	https://academic.oup.com/pcp/article-abstract/58/10/1801/4086060?redirectedFrom=fulltext
Doi	http://dx.doi.org/10.1093/pcp/pcx118
Keywords	Arabidopsis; ARF GEF; Auxin; Brefeldin A; PIN-FORMED1; trans-Golgi network
Description	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 BFA-induced 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.
Related projects:	CEITEC - Central European Institute of Technology Genetické studie k identifikaci molekulárních mechanizmu bunecné polarity a auxinového transportu v rostlinách