scholarly journals D-Xylose Sensing in Saccharomyces cerevisiae: Insights from D-Glucose Signaling and Native D-Xylose Utilizers

2021 ◽  
Vol 22 (22) ◽  
pp. 12410
Author(s):  
Daniel P. Brink ◽  
Celina Borgström ◽  
Viktor C. Persson ◽  
Karen Ofuji Osiro ◽  
Marie F. Gorwa-Grauslund

Extension of the substrate range is among one of the metabolic engineering goals for microorganisms used in biotechnological processes because it enables the use of a wide range of raw materials as substrates. One of the most prominent examples is the engineering of baker’s yeast Saccharomyces cerevisiae for the utilization of d-xylose, a five-carbon sugar found in high abundance in lignocellulosic biomass and a key substrate to achieve good process economy in chemical production from renewable and non-edible plant feedstocks. Despite many excellent engineering strategies that have allowed recombinant S. cerevisiae to ferment d-xylose to ethanol at high yields, the consumption rate of d-xylose is still significantly lower than that of its preferred sugar d-glucose. In mixed d-glucose/d-xylose cultivations, d-xylose is only utilized after d-glucose depletion, which leads to prolonged process times and added costs. Due to this limitation, the response on d-xylose in the native sugar signaling pathways has emerged as a promising next-level engineering target. Here we review the current status of the knowledge of the response of S. cerevisiae signaling pathways to d-xylose. To do this, we first summarize the response of the native sensing and signaling pathways in S. cerevisiae to d-glucose (the preferred sugar of the yeast). Using the d-glucose case as a point of reference, we then proceed to discuss the known signaling response to d-xylose in S. cerevisiae and current attempts of improving the response by signaling engineering using native targets and synthetic (non-native) regulatory circuits.

2020 ◽  
Vol 21 (23) ◽  
pp. 8938
Author(s):  
Sebastian Piłsyk ◽  
Urszula Perlinska-Lenart ◽  
Anna Janik ◽  
Elżbieta Gryz ◽  
Marta Ajchler-Adamska ◽  
...  

In a wide range of organisms, dolichyl phosphate mannose (DPM) synthase is a complex of tree proteins Dpm1, Dpm2, and Dpm3. However, in the yeast Saccharomyces cerevisiae, it is believed to be a single Dpm1 protein. The function of Dpm3 is performed in S. cerevisiae by the C-terminal transmembrane domain of the catalytic subunit Dpm1. Until present, the regulatory Dpm2 protein has not been found in S. cerevisiae. In this study, we show that, in fact, the Yil102c-A protein interacts directly with Dpm1 in S. cerevisiae and influences its DPM synthase activity. Deletion of the YIL102c-A gene is lethal, and this phenotype is reversed by the dpm2 gene from Trichoderma reesei. Functional analysis of Yil102c-A revealed that it also interacts with glucosylphosphatidylinositol-N-acetylglucosaminyl transferase (GPI-GnT), similar to DPM2 in human cells. Taken together, these results show that Yil102c-A is a functional homolog of DPMII from T. reesei and DPM2 from humans.


2006 ◽  
Vol 70 (1) ◽  
pp. 253-282 ◽  
Author(s):  
George M. Santangelo

SUMMARY Eukaryotic cells possess an exquisitely interwoven and fine-tuned series of signal transduction mechanisms with which to sense and respond to the ubiquitous fermentable carbon source glucose. The budding yeast Saccharomyces cerevisiae has proven to be a fertile model system with which to identify glucose signaling factors, determine the relevant functional and physical interrelationships, and characterize the corresponding metabolic, transcriptomic, and proteomic readouts. The early events in glucose signaling appear to require both extracellular sensing by transmembrane proteins and intracellular sensing by G proteins. Intermediate steps involve cAMP-dependent stimulation of protein kinase A (PKA) as well as one or more redundant PKA-independent pathways. The final steps are mediated by a relatively small collection of transcriptional regulators that collaborate closely to maximize the cellular rates of energy generation and growth. Understanding the nuclear events in this process may necessitate the further elaboration of a new model for eukaryotic gene regulation, called “reverse recruitment.” An essential feature of this idea is that fine-structure mapping of nuclear architecture will be required to understand the reception of regulatory signals that emanate from the plasma membrane and cytoplasm. Completion of this task should result in a much improved understanding of eukaryotic growth, differentiation, and carcinogenesis.


2005 ◽  
Vol 33 (5) ◽  
pp. 1170-1173 ◽  
Author(s):  
K. Liu ◽  
X. Zhang ◽  
C. Sumanasekera ◽  
R.L. Lester ◽  
R.C. Dickson

Over the past several years, studies of sphingolipid functions in the baker's yeast Saccharomyces cerevisiae have revealed that the sphingoid LCBs (long-chain bases), dihydrosphingosine and PHS (phytosphingosine), are important signalling molecules or second messengers under heat stress and during non-stressed conditions. LCBs are now recognized as regulators of AGC-type protein kinase (where AGC stands for protein kinases A, G and C) Pkh1 and Pkh2, which are homologues of mammalian phosphoinositide-dependent protein kinase 1. LCBs were previously shown to activate Pkh1 and Pkh2, which then activate the downstream protein kinase Pkc1. We have recently demonstrated that PHS stimulates Pkh1 to activate additional downstream kinases including Ypk1, Ypk2 and Sch9. We have also found that PHS acts downstream of Pkh1 and partially activates Ypk1, Ypk2 and Sch9. These kinases control a wide range of cellular processes including growth, cell wall integrity, stress resistance, endocytosis and aging. As we learn more about the cellular processes controlled by Ypk1, Ypk2 and Sch9, we will have a far greater appreciation of LCBs as second messengers.


Genetics ◽  
1990 ◽  
Vol 124 (3) ◽  
pp. 515-522
Author(s):  
L P Wakem ◽  
F Sherman

Abstract Approximately 290 omnipotent suppressors, which enhance translational misreading, were isolated in strains of the yeast Saccharomyces cerevisiae containing the psi+ extrachromosomal determinant. The suppressors could be assigned to 8 classes by their pattern of suppression of five nutritional markers. The suppressors were further distinguished by differences in growth on paromomycin medium, hypertonic medium, low temperatures (10 degrees), nonfermentable carbon sources, alpha-aminoadipic acid medium, and by their dominance and recessiveness. Genetic analysis of 12 representative suppressors resulted in the assignment of these suppressors to 6 different loci, including the three previously described loci SUP35 (chromosome IV), SUP45 (chromosome II) and SUP46 (chromosome II), as well as three new loci SUP42 (chromosome IV), SUP43 (chromosome XV) and SUP44 (chromosome VII). Suppressors belonging to the same locus had a wide range of different phenotypes. Differences between alleles of the same locus and similarities between alleles of different loci suggest that the omnipotent suppressors encode proteins that effect different functions and that altered forms of each of the proteins can effect the same function.


2020 ◽  
Vol 22 (1) ◽  
pp. 167
Author(s):  
Prajita Pandey ◽  
Khadiza Zaman ◽  
Laszlo Prokai ◽  
Vladimir Shulaev

The early signaling events involved in oxidant recognition and triggering of oxidant-specific defense mechanisms to counteract oxidative stress still remain largely elusive. Our discovery driven comparative proteomics analysis revealed unique early signaling response of the yeast Saccharomyces cerevisiae on the proteome level to oxidants with a different mechanism of action as early as 3 min after treatment with four oxidants, namely H2O2, cumene hydroperoxide (CHP), and menadione and diamide, when protein abundances were compared using label-free quantification relying on a high-resolution mass analyzer (Orbitrap). We identified significant regulation of 196 proteins in response to H2O2, 569 proteins in response to CHP, 369 proteins in response to menadione and 207 proteins in response to diamide. Only 17 proteins were common across all treatments, but several more proteins were shared between two or three oxidants. Pathway analyses revealed that each oxidant triggered a unique signaling mechanism associated with cell survival and repair. Signaling pathways mostly regulated by oxidants were Ran, TOR, Rho, and eIF2. Furthermore, each oxidant regulated these pathways in a unique way indicating specificity of response to oxidants having different modes of action. We hypothesize that interplay of these signaling pathways may be important in recognizing different oxidants to trigger different downstream MAPK signaling cascades and to induce specific responses.


Author(s):  
Elvira A. Islammagomedova ◽  
Eslanda A. Khalilova ◽  
Rasul Z. Gasanov ◽  
Aida A. Abakarova ◽  
Dinara A. Aliverdieva

The resistance of the yeast Saccharomyces cerevisiae DAW-3а and Y-503 to the conditions of extreme values of pH, NaCl, temperature has been studied. Under different cultivation modes, the rounded shape of DAW-3a cells is pre-served and this parameter Y-503 changes. Under conditions of different pH values and 30°C, the maximum sizes of cells and giant colonies of the polyploid Y-503 strain were found in comparison with the haploid DAW-3a; at 37°C, the advantage of Y-503 was not observed and the colony sizes of both strains were practically the same. The reaction of the strains to critical concentrations of NaCl in the medium was identical: a decrease in the size of cells and colonies was found; change in the shape, surface, color and structure of colonies. Under conditions of the simultaneous influence of an elevated temperature of 37°C, a wide range of pH and 5 % NaCl, the cell size decreased slightly; under neutral and alkaline conditions of cultivation, a slightly greater tolerance of yeast to salt stress was established; a decrease in the size of giant colonies was found, while the maximum size of the studied strains was noted at pH 11.0, the minimum at pH 3.0. The study of the tolerance of the yeast S. cerevisiae DAW-3a and Y-503 to extreme factors is of particular interest in connection with the possibility of using stress-resistant strains in biotechnological processes.


Author(s):  
Anna Ylinen ◽  
Hannu Maaheimo ◽  
Adina Anghelescu-Hakala ◽  
Merja Penttilä ◽  
Laura Salusjärvi ◽  
...  

Abstract Polyhydroxyalkanoates (PHA) provide biodegradable and bio-based alternatives to conventional plastics. Incorporation of 2-hydroxy acid monomers into polymer, in addition to 3-hydroxy acids, offers possibility to tailor the polymer properties. In this study, poly(D-lactic acid) (PDLA) and copolymer P(LA-3HB) were produced and characterized for the first time in the yeast Saccharomyces cerevisiae. Expression of engineered PHA synthase PhaC1437Ps6–19, propionyl-CoA transferase Pct540Cp, acetyl-CoA acetyltransferase PhaA, and acetoacetyl-CoA reductase PhaB1 resulted in accumulation of 3.6% P(LA-3HB) and expression of engineered enzymes PhaC1Pre and PctMe resulted in accumulation of 0.73% PDLA of the cell dry weight. According to NMR, P(LA-3HB) contained D-Lactic acid repeating sequences. For reference, expression of PhaA, PhaB1, and PHA synthase PhaC1 resulted in accumulation 11% poly(hydroxybutyrate) (PHB) of the cell dry weight. Weight average molecular weights of these polymers were comparable to similar polymers produced by bacterial strains, 24.6 kDa, 6.3 kDa, and 1 130 kDa, for P(LA-3HB), PDLA, and PHB, respectively. The results suggest that yeast, as a robust and acid tolerant industrial production organism, could be suitable for production of 2-hydroxy acid containing PHAs from sugars or from 2-hydroxy acid containing raw materials. Moreover, the wide substrate specificity of PHA synthase enzymes employed increases the possibilities for modifying copolymer properties in yeast in the future.


2019 ◽  
Vol 12 (4) ◽  
Author(s):  
L. Levandovsky ◽  
М. Kravchenko

The article presents the results of investigating how the intensity of aerating the medium effects on the cultivation process and the metabolic activity of alcoholic yeast Saccharomyces cerevisiae, strain U-563, in the modern technology of alcohol and baking yeast from molasses. The chemical and technological parameters of media at the aerobic and anaerobic stages of the process, the level of accumulation of the major and secondary products of yeast metabolism, and their enzymatic activity have been determined by methods commonly employed in science and in the practice of alcohol biotechnology. The objects of research were the yeast Saccharomyces cerevisiae, molasses wort, the medium in the process of yeast cultivation, and fermented wash. It has been established that two factors are the most important in the accumulation of alcoholic yeast biomass: the intensity of aerating the medium, and the staged introduction of the substrate during biomass cultivation. The more aerated the medium, the more intensively secondary metabolites of yeast Saccharomyces cerevisiae are formed (glycerol, aldehydes, higher alcohols, volatile acids, and esters) – both at the yeast generation stage and during anaerobic fermentation. When yeast Saccharomyces cerevisiae is grown in a gradient-continuous manner in a battery of series-connected apparatuses, with undiluted substrate (molasses) added by degrees, yeast biosynthesis is significantly enhanced compared to the traditional homogeneous-continuous method. The results obtained indicate the active metabolism of carbohydrates in the Krebs cycle, when the medium is intensively aerated. Besides, the results reveal the high reactivity of aldehydes and esters that results in their transformation into other compounds, and in a great decrease in their amount at the anaerobic stage of the process. However, a progressive increase is observed in glycerol, higher alcohols, and volatile acids, starting from the first yeast generator and up to the last fermentation apparatus, irrespective of the level of aerating the medium during yeast cultivation. These findings can be effectively used to manufacture food, technical, and fuel ethanol industrially from sugar-based raw materials in the course of co-production of alcohol and baking yeast.


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