2023 31 B2

The Effects of Lithium Toxicity on Vacuole Function and Dynamics in Saccharomyces cerevisiae

By: Daniel Knapp, Gabriela Turcios

Department: Biology

Faculty Advisor: Dr. Mark Chan

Metallic compounds, such as lithium, disrupt cellular biochemical mechanisms under toxic conditions. In Saccharomyces cerevisiae, budding yeast, vacuoles are membrane-bound organelles crucial for metal detoxification, protein degradation, and cellular homeostasis. This study investigates the effects of lithium on vacuole inheritance, a key aspect of organelle mechanics. Understanding organelle response to metals will provide insights into cellular dynamics. Preliminary data revealed a reduction in vacuole inheritance during cell division upon lithium exposure. To study this novel phenomenon, budding yeast strain BY4741, with a GFP-tagged vacuole membrane, was exposed to LiCl in Sc - his media. Images were captured using spinning disc confocal microscopy and analyzed in ImageJ to determine inheritance defects in cell pairs. A statistically significant increase in inheritance defects was observed between control and lithium-exposed cell populations. Possible mechanisms behind this novel phenotype include lithium's inhibition of IMPase or kinases Mck1/Rim11. Future experiments to further understand this phenomenon include FM464 dye staining to confirm the phenotype and RNA-sequencing to detect changes in gene expression, specifically in vac8/17, essential genes for vacuole inheritance. These experiments will help elucidate the molecular mechanisms disrupting vacuole inheritance under lithium toxicity, furthering our understanding of organelle dynamics and its influence on the cell.