Presenter(s): Zack Basham—Biochemistry
Faculty Mentor(s): David Garcia
Session: Prerecorded Poster Presentation
Pseudouridine synthases are critical RNA modifiers in eukaryotes . One member of this family of enzymes, encoded by the Pus4 gene in the budding yeast Saccharomyces cerevisiae, forms a prion protein, named [BIG+] . Rather than resulting in cell death, as for known mammalian prion diseases, [BIG+] promotes increased cell proliferation and cell size . These observations raise the question of how the prion promotes cell growth . The increased cell size and growth rate suggests an alteration to a fundamental eukaryotic growth control pathway, mediated by the TOR complex (“target of rapamycin”) . One target of TOR, a protein kinase, is Sch9, an AGC kinase, which is activated via phosphorylation by the TOR complex . Sch9 is involved in multiple processes essential for growth such as ribosome biogenesis, translation control, and cAPK activity . To better understand the relationship between [BIG+] and TOR, we have introduced hyperactive mutants of TOR or Sch9 into [BIG+] and naive cells . By monitoring growth rate in media with varying levels of arginine, we can monitor [BIG+] response to different nutrient conditions . We have also made progress in monitoring the expression of Sch9 in [BIG+] cells compared to cells without the prion . This contributes to our understanding of how the prion and TOR complex are interacting to affect cell growth .