CD-Laboratory for Biotechnology of Glycerol, Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria.
Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria.
Yeast. 2022 May;39(5):323-336. doi: 10.1002/yea.3702. Epub 2022 Mar 29.
Cellular membranes separate cells from the environment and hence, from molecules essential for their survival. To overcome this hurdle, cells developed specialized transport proteins for the transfer of metabolites across these membranes. Crucial metabolites that need to cross the membrane of each living organism, are the carbon sources. While many organisms prefer glucose as a carbon source, the yeast Yarrowia lipolytica seems to favor glycerol over glucose. The fast growth of Y. lipolytica on glycerol and its flexible metabolism renders this yeast a fascinating organism to study the glycerol metabolism. Based on sequence similarities to the known fungal glycerol transporter ScStl1p and glycerol channel ScFps1p, ten proteins of Y. lipolytica were found that are potentially involved in glycerol uptake. To evaluate, which of these proteins is able to transport glycerol in vivo, a complementation assay with a glycerol transport-deficient strain of Saccharomyces cerevisiae was performed. Six of the ten putative transporters enabled the growth of S. cerevisiae stl1Δ on glycerol and thus, were confirmed as glycerol transporting proteins. Disruption of the transporters in Y. lipolytica abolished its growth on 25 g/L glycerol, but the individual expression of five of the identified glycerol transporters restored growth. Surprisingly, the transporter-disrupted Y. lipolytica strain retained its ability to grow on high glycerol concentrations. This study provides insight into the glycerol uptake of Y. lipolytica at low glycerol concentrations through the characterization of six glycerol transporters and indicates the existence of further mechanisms active at high glycerol concentrations.
细胞膜将细胞与环境隔开，因此也将细胞与生存所必需的分子隔开。为了克服这一障碍，细胞开发了专门的转运蛋白，用于将代谢物穿过这些膜进行转运。需要穿过每种生物膜的关键代谢物是碳源。虽然许多生物更喜欢葡萄糖作为碳源，但酵母解脂耶氏酵母似乎更倾向于甘油而不是葡萄糖。解脂耶氏酵母能够快速利用甘油生长，并且其代谢方式灵活，这使得该酵母成为研究甘油代谢的理想生物。根据与已知真菌甘油转运蛋白 ScStl1p 和甘油通道 ScFps1p 的序列相似性，发现了酵母解脂耶氏酵母中 10 种可能参与甘油摄取的蛋白质。为了评估这些蛋白质中哪些能够在体内转运甘油，我们对酿酒酵母甘油转运缺陷株进行了互补测定。在酿酒酵母 stl1Δ 中，这 10 种假定转运蛋白中的 6 种能够使其在甘油上生长，因此被确认为甘油转运蛋白。在酵母解脂耶氏酵母中敲除这些转运蛋白会使其丧失在 25g/L 甘油上的生长能力，但鉴定出的 5 种甘油转运蛋白的单独表达可恢复生长。令人惊讶的是，敲除转运蛋白的酵母解脂耶氏酵母菌株仍保留了在高甘油浓度下生长的能力。本研究通过对 6 种甘油转运蛋白的特性进行分析，深入了解了酵母解脂耶氏酵母在低甘油浓度下对甘油的摄取情况，并表明在高甘油浓度下还存在其他活跃的机制。
