The Saccharomyces cerevisiae Snf1 complex is a member of the AMP-activated protein kinase family and plays an important role in response to environmental stress. The α catalytic subunit Snf1 regulates the activity of the protein kinase, while the β regulatory subunits Sip1/Sip2/Gal83 specify substrate preferences and stress response capacities of Snf1. In this study, we aim to investigate the effects of SNF1 overexpression on the cell tolerance and glucose consumption of S. cerevisiae in high glucose, ethanol, and heat stresses and to explore the valid Snf1 form in the light of β subunits in these stresses. The results suggest that overexpression of SNF1 is effective to improve cell resistance and glucose consumption of S. cerevisiae in high glucose, ethanol, and heat stresses, which might be related to the changed accumulation of fatty acids and amino acids and altered expression levels of genes involved in glucose transport and glycolysis. However, different form of β regulatory subunits dominated in stresses with regard to cell tolerance and glucose utilization. The Sip1 isoform was more necessary to the growth and glucose consumption in ethanol stress. The glucose uptake largely depended on the Sip2 isoform in high sugar and ethanol stresses. The Gal83 isoform only contributed inferior effect on the growth in ethanol stress. Therefore, redundancy and synergistic effect of β subunits might occur in high glucose, ethanol, and heat stresses, but each subunit showed specificity under various stresses. This study enriches the understanding of the function of Snf1 protein kinase and provides an insight to breed multi-stress tolerant yeast strains.

中文翻译：

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通过过度表达SNF1基因和Snf1的各种β亚型，增强了酿酒酵母的多压力耐受性和葡萄糖利用，在压力中占主导地位。

酿酒酵母Snf1复合物是AMP激活的蛋白激酶家族的成员，在应对环境压力中起重要作用。α催化亚基Snf1调节蛋白激酶的活性，而β调节亚基Sip1 / Sip2 / Gal83指定底物偏好和应力响应能力。在这项研究中，我们旨在研究SNF1过表达对高糖，乙醇和热胁迫下酿酒酵母的细胞耐受性和葡萄糖消耗的影响，并根据这些应激中的β亚基探索有效的Snf1形式。结果表明，在高葡萄糖，乙醇和热胁迫下，SNF1的过度表达可有效提高酿酒酵母的细胞抗药性和葡萄糖消耗，这可能与脂肪酸和氨基酸积累的变化以及参与葡萄糖转运和糖酵解的基因表达水平的变化有关。然而，就细胞耐受性和葡萄糖利用而言，不同形式的β调节亚基在应激中起主导作用。Sip1亚型对乙醇胁迫下的生长和葡萄糖消耗更为必要。在高糖和乙醇胁迫下，葡萄糖的吸收主要取决于Sip2同工型。Gal83同工型仅对乙醇胁迫的生长起不利作用。因此，在高葡萄糖，乙醇和热胁迫下，β亚基可能会产生冗余和协同效应，但每个亚基在各种胁迫下均表现出特异性。