The Inhibitor Endosidin 4 Targets SEC7 Domain-Type ARF GTPase Exchange Factors and Interferes with Subcellular Trafficking in Eukaryotes
| Authors | |
|---|---|
| Year of publication | 2018 |
| Type | Article in Periodical |
| Magazine / Source | Plant Cell |
| MU Faculty or unit | |
| Citation | |
| Web | https://academic.oup.com/plcell/article/30/10/2553/6099476?login=true |
| Doi | http://dx.doi.org/10.1105/tpc.18.00127 |
| Keywords | GUANINE-NUCLEOTIDE-EXCHANGE; ADP-RIBOSYLATION FACTOR-1; AUXIN EFFLUX CARRIER; TRANS-GOLGI NETWORK; ENDOPLASMIC-RETICULUM; YEAST GOLGI; ARABIDOPSIS-THALIANA; ROOT GRAVITROPISM; BREFELDIN-A; INDUCED HAPLOINSUFFICIENCY |
| Description | The trafficking of subcellular cargos in eukaryotic cells crucially depends on vesicle budding, a process mediated by ARFGEFs (ADP-ribosylation factor guanine nucleotide exchange factors). In plants, ARF-GEFs play essential roles in endocytosis, vacuolar trafficking, recycling, secretion, and polar trafficking. Moreover, they are important for plant development, mainly through controlling the polar subcellular localization of PIN-FORMED transporters of the plant hormone auxin. Here, using a chemical genetics screen in Arabidopsis thaliana, we identified Endosidin 4 (ES4), an inhibitor of eukaryotic ARF-GEFs. ES4 acts similarly to and synergistically with the established ARF-GEF inhibitor Brefeldin A and has broad effects on intracellular trafficking, including endocytosis, exocytosis, and vacuolar targeting. Additionally, Arabidopsis and yeast (Saccharomyces cerevisiae) mutants defective in ARF-GEF show altered sensitivity to ES4. ES4 interferes with the activation-based membrane association of the ARF1 GTPases, but not of their mutant variants that are activated independently of ARF-GEF activity. Biochemical approaches and docking simulations confirmed that ES4 specifically targets the SEC7 domain-containing ARF-GEFs. These observations collectively identify ES4 as a chemical tool enabling the study of ARF-GEF-mediated processes, including ARF-GEF-mediated plant development. |
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