The Effects of the Pho85 Signaling Pathway on the Invertase Biosynthesis and Glucose Uptake in Saccharomyces cerevisiae

Authors: SEZAİ TÜRKEL, ELİF ARIK

Abstract: Glucose signaling controls a wide range of metabolic events in the yeast Saccharomyces cerevisiae. Glucose sensing and signaling processes require a variety of membrane-bound and cytoplasmic sensor proteins. Pho85p is a cyclin-dependent protein kinase that controls different metabolic events upon binding to its cyclin partners in the cytoplasm of yeast cells. In this study, we investigated the roles of Pho85p in the glucose signaling pathways that control invertase biosynthesis and glucose uptake in yeast. The biosynthesis of invertase enzyme from the SUC2 gene is controlled by glucose repression and derepression mechanisms in S. cerevisiae. However, the results of this research indicated that invertase biosynthesis occurs at low levels in a deregulated manner in the \Deltapho85 mutant yeast strain. Furthermore, our results showed that the biosynthesis of invertase is not repressed when the \Deltapho85 mutant is exposed to high levels of glucose. Moreover, we found that the glucose consumption rate of the \Deltapho85 mutant is at least 2-fold lower than that of the wild-type yeast strain. Our results indicated that Pho85p functions are essential for the regulated biosynthesis of the invertase enzyme from the SUC2 gene and for the high levels of glucose uptake in S. cerevisiae.

Keywords: Pho85, glucose sensing, glucose uptake, Saccharomyces cerevisiae, invertase

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