The effects of the Pho85 signaling pathway on invertase biosynthesis and glucose uptake in Saccharomyces cerevisiae

Glukoz sinyali Saccharomyces cerevisiae’da çok çeşitli metabolik olayları kontrol eder. Glukozun algılanması ve sinyal iletimi işlemi için hücre zarı ve sitoplazmasında bulunan çeşitli sensor proteinler gereklidir. Pho85p, sikline bağlı bir protein kinaz olup ilgili siklin proteinlerine bağlanarak maya hücreleri sitoplazmasında farklı metabolic olayları kontrol eder. Bu çalışmada Pho85p’nin glukoz alımı ve invertaz enzimi biyosentezini kontrol eden glukoz sinyal iletimi yolağındaki işlevleri araştırıldı. S. cerevisiae’da invertaz enziminin SUC2 geninden biyosentezi glukoz baskılanması ve baskının kaldırılması mekanizması ile kontrol edilir. Bununla birlikte, bu araştırmada elde edilen sonuçlar Δpho85 mutantı maya hücrelerinde invertaz biyosentezinin düşük seviyede ve düzensiz olarak meydana geldiğini göstermektedir. Buna ek olarak, elde ettiğimiz sonuçlar Δpho85 mutantına yüksek glukoz uygulandığında invertaz biyosentezinin baskılanmadığını göstermektedir. Ayrıca, Δpho85 mutantında glukoz tüketim hızının yaban tip mayaya göre en az 2 kat daha düşük olduğunu belirledik. Sonuçlarımız S. cerevisiae’da Pho85 işlevinin SUC2 geninden invertaz biyosentezinin kontrol edilmesi ve yüksek oranda glukoz alımı için gerekli olduğunu göstermektedir.

Saccharomyces cerevisiae’da Pho85 sinyal iletim yolağının invertaz biyosentezi ve glukoz alımına etkileri

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 Δpho85mutant yeast strain. Furthermore, our results showed that the biosynthesis of invertase is not repressed when the Δpho85 mutant is exposed to high levels of glucose. Moreover, we found that the glucose consumption rate of the Δpho85 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.

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