Enhanced multi-stress tolerance and glucose utilization of Saccharomyces cerevisiae by overexpression of the SNF1 gene and varied beta isoform of Snf1 dominates in stresses

Abstract

Background 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. Results 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. Conclusions This study enriches the understanding of the function of Snf1 protein kinase and provides an insight to breed multi-stress tolerant yeast strains.

Effect of overexpression of SNF1 on the transcriptional and metabolic landscape of baker’s yeast under freezing stress

“…The change of each amino acid was not the same in SNF1 overexpression under different conditions, such as that in freezing and non-freezing in this work and that in high glucose, ethanol, and heat shock stresses of our previous study [33]. In addition, Nicastro et al [42] showed that Snf1 inhibited the biosynthesis of amino acids in amino acid-rich condition.…”

“…Related studies have shown that the fermentation ability of proline-accumulating baker’s yeast in frozen dough is higher than that of the wild strain [ 31 ]. The content of glycerol, a well-known metabolite as a cell cryoprotectant [ 32 , 33 ], was significantly upregulated in the transformant ABY+S. In addition, three substances in the differential metabolites were related to cell membrane components: upregulated palmitic acid and downregulated sn-1LysoPC (16:0) and sn-1LysoPE (18:1).…”

SNF1β-Modulated Glucose Uptake and the Balance between Polyunsaturated Fatty Acids and Carbohydrates in Mortierella alpina

“…Currently, research goals in developing the biotechnological application of oleaginous microorganisms focus on enhancing target PUFA yield and reducing the production cost . For heterotrophic oleaginous microorganisms, the glucose utilization rate is a determinant factor that affects fermentation cost and final lipid yield . To enhance glucose utilization, genes involved in glucose transportation and metabolism have been modified to strengthen the allocation of carbon flux toward lipid synthesis. , In addition, some protein kinases with global regulatory roles also attract research interest. , Among them, the heterotrimeric sucrose nonfermentable protein kinase 1 (SNF1), homolog of mammal adenosine monophosphate-activated protein kinase (AMPK), is one of the well-known global regulators that plays a vital role in lipogenesis and cellular responses to nutrient levels.…”

“…7 For heterotrophic oleaginous microorganisms, the glucose utilization rate is a determinant factor that affects fermentation cost and final lipid yield. 8 To enhance glucose utilization, genes involved in glucose transportation and metabolism have been modified to strengthen the allocation of carbon flux toward lipid synthesis. 6,9 In addition, some protein kinases with global regulatory roles also attract research interest.…”

Role of Elm1, Tos3, and Sak1 Protein Kinases in the Maltose Metabolism of Baker’s Yeast

“…The Snf1 protein kinase is a complex that consists of an alpha catalytic subunit Snf1, a gamma regulatory subunit Snf4, and one of the three alternative beta regulatory subunits, namely, Sip1, Sip2, and Gal83 (Daniel and Carling, 2002;García-Salcedo et al, 2014;Meng et al, 2020). Snf1 activation requires at least two steps: First, Snf4 binds to the C-terminal regulatory domain of the catalytic subunit Snf1 to counteract the autoinhibition of Snf1, in which β regulatory subunits participate in the linkage of Snf1 and Snf4, and direct the subcellular localization of Snf1 (McCartney and Schmidt, 2001).…”