Chemical genomics screening for biomodulators of endomembrane system trafficking

Cell proteins traffic through complex and tightly regulated pathways. Although the endomembrane system is essential, its different pathways are still not well understood. In order to dissect protein trafficking pathways, chemical genomic screenings have been performed. This strategy has been utilized to successfully discover bioactive chemicals with a specific cellular action and in most cases, tunable and reversible effects. Once the bioactive chemical is identified, further strategies can be used to find the target proteins that are important for functionality of trafficking pathways. This approach can be combined with the powerful genetic tools available for model organisms. Drug-hypersensitive and drug-resistant mutant isolation can lead to the identification of cellular pathways affected by a bioactive chemical and reveal its protein target(s). Here, we describe an approach to look for hypersensitive and resistant mutants to a specific bioactive chemical that affects protein trafficking in yeast. This approach can be followed and adapted to any other pathway or cellular process that can be screened phenotypically, serving as a guide for novel screens in yeast. More importantly, information provided by this approach can potentially be extrapolated to other organisms like plants. Thus, the method described can be of broad utility to plant biologists.