Identification of functional partners of translation Elongation Factor 3 in Saccharomyces cerevisiae

Fungal infections are responsible for 1.6 million human deaths each year. Additionally, fungal pathogens damage a significant portion of food crops. The number of effective anti‐fungal drugs available is small and many have serious side effects. Furthermore, most of these drugs target aspects of the cell membrane, offering a limited selection as cases of resistance increase. While protein synthesis is not a common focus for drug discovery because of similarities between fungi and host cells, eukaryotic Elongation Factor 3 (eEF3) is highly conserved in fungi but not found in higher eukaryotes. This makes it an excellent target for novel anti‐fungal drugs. eEF3 interacts with the ribosome during the translation elongation step of protein synthesis and is essential for yeast survival. However, little is known about the functional partners of eEF3. We are identifying genes that influence this factor with a screen for suppressors of a conditional eEF3 mutant. The mutant contains two missense mutations F803A R806A in a unique chromodomain insertion in the second ATP binding domain of eEF3 that shows significant interactions with multiple ribosome components by cryo‐EM. Through UV mutagenesis, we randomly generated putative suppressor mutations that restore growth at 37°C to the eEF3 temperature‐sensitive phenotype. Eleven strains showed improved growth rate, reduced temperature sensitivity, and many have altered susceptibility to translation‐inhibiting drugs. Whole genome sequencing of the putative suppressors showed multiple genes potentially involved in eEF3 function. Further analysis of the mutations in these proposed suppressor genes will determine their impact on cell function. These experiments will lay the foundation for the development of a novel class of anti‐fungal therapeutics that target eEF3. Support or Funding Information National Institutes of Health RO1 GM57483