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

Plant Cell Physiol. 2017 Oct 1;58(10):1801-1811. doi: 10.1093/pcp/pcx118.


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.

Keywords: ARF GEF; Arabidopsis; Auxin; Brefeldin A; PIN-FORMED1; trans-Golgi network.

MeSH terms

  • ADP-Ribosylation Factors / genetics
  • ADP-Ribosylation Factors / metabolism*
  • Alleles
  • Arabidopsis / drug effects
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Brefeldin A / pharmacology*
  • Cell Compartmentation
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Cloning, Molecular
  • Codon, Nonsense / genetics
  • Endosomes / drug effects
  • Endosomes / metabolism*
  • Green Fluorescent Proteins / metabolism
  • Guanine Nucleotide Exchange Factors / metabolism*
  • Phenotype
  • Protein Transport / drug effects
  • Seedlings / drug effects
  • Seedlings / growth & development
  • trans-Golgi Network / drug effects
  • trans-Golgi Network / metabolism*


  • Arabidopsis Proteins
  • Codon, Nonsense
  • Guanine Nucleotide Exchange Factors
  • big2 protein Arabidopsis
  • Green Fluorescent Proteins
  • Brefeldin A
  • ADP-Ribosylation Factors