Elucidating the Effects of Restrictive Temperatures on the Function of Arl1p in Ion Homeostasis in Saccharomyces cerevisiae

Abstract

Strict regulation of ion homeostasis is necessary for cell function and survival. Arl1p, a member of the ADPribosylation factor-like protein family, is known to function in ion homeostasis by mediating lithium (Li⁺) tolerance and regulating potassium ion (K+) influx in Saccharomyces cerevisiae. Given that arl1Δ mutants show temperature sensitivity, this study investigates the effects of restrictive temperatures on the function of Arl1p in regulating Li⁺ tolerance and the role of K+ in enhancing Li⁺ tolerance. We have characterized cell growth rates of arl1Δ mutant and wild-type cells in the presence of Li⁺ and K⁺ at optimal (30℃) and restrictive (37℃) temperatures using haemocytometry. We report that Li⁺ sensitivity was exacerbated at restrictive temperatures in the wild-type cells, but not in arl1Δ mutants, suggesting the potential temperature sensitivity of Arl1p. Further, we report that K⁺ was sufficient to suppress Li⁺-induced decreases in cell growth in wildtype and arl1Δ mutant cells at optimal and restrictive temperatures, suggesting that K⁺ functions as a growth factor in S. cerevisiae. Future studies may aim to further elucidate the relationship between temperature and ion homeostasis.