The exocyst complex regulates the last steps of exocytosis, which is essential to organisms across kingdoms. In humans, its dysfunction is correlated with several significant diseases, such as diabetes and cancer progression. Investigation of the dynamic regulation of the evolutionarily conserved exocyst-related processes using mutants in genetically tractable organisms such as Arabidopsis thaliana is limited by the lethality or the severity of phenotypes. We discovered that the small molecule Endosidin2 (ES2) binds to the EXO70 (exocyst component of 70 kDa) subunit of the exocyst complex, resulting in inhibition of exocytosis and endosomal recycling in both plant and human cells and enhancement of plant vacuolar trafficking. An EXO70 protein with a C-terminal truncation results in dominant ES2 resistance, uncovering possible distinct regulatory roles for the N terminus of the protein. This study not only provides a valuable tool in studying exocytosis regulation but also offers a potentially new target for drugs aimed at addressing human disease.

Center for Plant Cell Biology Institute for Integrative Genome Biology University of California Riverside CA 92521; Department of Botany and Plant Sciences University of California Riverside CA 92521;

Department of Biochemistry University of California Riverside CA 92521;

Department of Bioengineering University of California Riverside CA 92521;

Department of Biology University of Pennsylvania Philadelphia PA 19104;

Department of Biology Wake Forest University Winston Salem NC 27109; Center for Molecular Communication and Signaling Wake Forest University Winston Salem NC 27109;

Department of Chemistry University of California Riverside CA 92521;

Institute of Experimental Botany Academy of Sciences 165 02 Prague 6 Czech Republic;

Institute of Experimental Botany Academy of Sciences 165 02 Prague 6 Czech Republic; Department of Experimental Plant Biology Faculty of Sciences Charles University 128 43 Prague 2 Czech Republic

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Proc Natl Acad Sci U S A. 2016 Jan 5;113(1):14-6. doi: 10.1073/pnas.1522317113. PubMed

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PDB
4RL5