Nonselective chemical inhibition of Sec7 domain-containing ARF-GEFs in Arabidopsis ($) (Plant Cell)

ARF GEFs (ADP-ribosylation factor guanine nucleotide exchange factors) play a major role in the intracellular trafficking and eventually regulate developmental cues. As plants contain multiple ARF GEF with very similar sequences, chemical genetics approaches are more appropriate to uncover their function compared to classic genetic strategies. The fungal toxin Brefeldin A (BFA) targets the SEC7 domain of ARF-GEFs but does not inhibit all of them. In this study, the authors identified a novel inhibitor, Secdin, which inhibits both BFA-sensitive and BFA-insensitive ARF-GEFs. Interestingly, this inhibition is not SEC7 domain-mediated. As a result, Secdin can be used to understand the roles of these BFA-insensitive ARF GEFs. (See also this companion paper describing the characterization of another ARF GEF inhibitor, Endosidin). (Summary by Arif Ashraf) Plant Cell: 10.1105/tpc.18.00145