scholarly journals Mitochondrial respiration is required to provide amino acids during fermentative proliferation of fission yeast

EMBO Reports ◽  
2020 ◽  
Vol 21 (11) ◽  
Author(s):  
Michal Malecki ◽  
Stephan Kamrad ◽  
Markus Ralser ◽  
Jürg Bähler
Keyword(s):  
Amino Acids ◽  
Fission Yeast ◽  
Mitochondrial Respiration

scholarly journals Mitochondrial respiration is required to provide amino acids during fermentative proliferation of fission yeast

2020 ◽  
Author(s):  
Michal Malecki ◽  
Stephan Kamrad ◽  
Markus Ralser ◽  
Jürg Bähler
Keyword(s):  
Amino Acids ◽  
Fission Yeast ◽  
Mitochondrial Respiration ◽  
Aerobic Glycolysis ◽  
Krebs Cycle ◽  
Yeast Cells ◽  
Limiting Factors ◽  
Gene Expression Response ◽  
Atp Production ◽  
Expression Response

AbstractWhen glucose is available, many organisms repress mitochondrial respiration in favour of aerobic glycolysis, or fermentation in yeast, that suffices for ATP production. Fission yeast cells, however, rely partially on respiration for rapid proliferation under fermentative conditions. Here we determined the limiting factors that require respiratory function during fermentation. When the electron transport chain was inhibited, supplementation with arginine was necessary and sufficient to restore rapid cell proliferation. Accordingly, a systematic screen for mutants growing poorly without arginine identified not only mutants defective in arginine synthesis but also mutants defective in mitochondrial oxidative metabolism. Genetic or pharmacological inhibition of respiration triggered a drop in intracellular levels of arginine and amino acids derived from the Krebs-cycle metabolite alpha-ketoglutarate: glutamine, lysine and glutamic acid. Conversion of arginine into these amino acids was required for rapid proliferation when the respiratory chain was blocked. The respiratory block triggered an immediate gene-expression response diagnostic of TOR inhibition, which was muted by arginine supplementation or without the AMPK-activating kinase Ssp1. The TOR-controlled proteins featured biased composition of amino acids reflecting their shortage after respiratory inhibition. We conclude that respiration supports rapid proliferation in fermenting cells of fission yeast by boosting the supply of Krebs-cycle derived amino acids.

scholarly journals Amino acids whose intracellular levels change most during aging alter chronological lifespan of fission yeast

2020 ◽  
Author(s):  
Charalampos Rallis ◽  
Michael Mülleder ◽  
Graeme Smith ◽  
Yan Zi Au ◽  
Markus Ralser ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Fission Yeast ◽  
Yeast Cells ◽  
Total Amino Acid ◽  
Wild Type ◽  
Chronological Lifespan ◽  
Biomarkers Of Aging ◽  
Concentration Changes ◽  
Amino Acid Levels

AbstractAmino acid deprivation or supplementation can affect cellular and organismal lifespan, but we know little about the role of concentration changes in free, intracellular amino acids during aging. Here, we determine free amino-acid levels during chronological aging of non-dividing fission yeast cells. We compare wild-type with long-lived mutant cells that lack the Pka1 protein of the protein kinase A signalling pathway. In wild-type cells, total amino-acid levels decrease during aging, but much less so in pka1 mutants. Two amino acids strongly change as a function of age: glutamine decreases, especially in wild-type cells, while aspartate increases, especially in pka1 mutants. Supplementation of glutamine is sufficient to extend the chronological lifespan of wild-type but not of pka1Δ cells. Supplementation of aspartate, on the other hand, shortens the lifespan of pka1Δ but not of wild-type cells. Our results raise the possibility that certain amino acids are biomarkers of aging, and their concentrations during aging can promote or limit cellular lifespan.

scholarly journals Phosphorylation of Arp2 is not essential for Arp2/3 complex activity in fission yeast

2018 ◽  
Vol 1 (5) ◽  
pp. e201800202 ◽  
Author(s):  
Alexander E Epstein ◽  
Sofia Espinoza-Sanchez ◽  
Thomas D Pollard
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Fission Yeast ◽  
Aspartic Acid ◽  
Actin Filaments ◽  
Yeast Genome ◽  
Complex Activity ◽  
Actin Patch

LeClaire et al presented evidence that phosphorylation of three sites on the Arp2 subunit activates the Arp2/3 complex to nucleate actin filaments. We mutated the homologous residues of Arp2 (Y198, T233, and T234) in the fission yeast genome to amino acids that preclude or mimic phosphorylation. Arp2/3 complex is essential for the viability of fission yeast, yet strains unable to phosphorylate these sites grew normally. Y198F/T233A/T234A Arp2 was only nonfunctional if GFP-tagged, as observed by LeClaire et al in Drosophila cells. Replacing both T233 and T234 with aspartic acid was lethal, suggesting that phosphorylation might be inhibitory. Nevertheless, blocking phosphorylation at these sites had the same effect as mimicking it: slowing assembly of endocytic actin patches. Mass spectrometry revealed phosphorylation at a fourth conserved Arp2 residue, Y218, but both blocking and mimicking phosphorylation of Y218 only slowed actin patch assembly slightly. Therefore, phosphorylation of Y198, T233, T234, and Y218 is not required for the activity of fission yeast Arp2/3 complex.

Cloning and sequencing of the cyclin-related cdc13+ gene and a cytological study of its role in fission yeast mitosis

1988 ◽  
Vol 91 (4) ◽  
pp. 587-595 ◽  
Author(s):  
I. Hagan ◽  
J. Hayles ◽  
P. Nurse
Keyword(s):  
Amino Acids ◽  
Protein Kinase ◽  
Fission Yeast ◽  
Gene Function ◽  
Mammalian Cells ◽  
Major Part ◽  
Cytological Study ◽  
Partial Loss ◽  
Cloning And Sequencing ◽  
Microtubular Cytoskeleton

We have cloned and sequenced the cdc13+ gene from fission yeast. When a major part of the cdc13+ gene is deleted from the chromosome, cells arrest in interphase, but partial loss of gene activity leads to cells containing condensed chromosomes, aberrant septa and a microtubular cytoskeleton with characteristics of both G2 and M. Expression of this phenotype is influenced by the nutritional status of the cell. Our results suggest that the cdc13+ gene function is required for the control of the G2 to M transition. It appears to play a role in regulating the separate pathways of events involved in the physical process of mitosis, for example in the reorganization of the cytoskeleton on transition from G2 to mitosis. The cdc13+ gene function interacts closely with both the yeast and human homologues of cdc2+, suggesting that mammalian cells may contain a cdc13+ homologue. The gene encodes a putative polypeptide of 482 amino acids, and a central region of 176 amino acids of this polypeptide is 50% identical with sea urchin cyclin. Therefore, the cdc13+ protein is cyclin related and could act as a regulator or substrate of the p34cdc2 protein kinase, which initiates mitosis.

scholarly journals Ammonia inhibits energy metabolism in astrocytes in a rapid and glutamate dehydrogenase 2-dependent manner

2020 ◽  
Vol 13 (10) ◽  
pp. dmm047134
Author(s):  
Leonie Drews ◽  
Marcel Zimmermann ◽  
Philipp Westhoff ◽  
Dominik Brilhaus ◽  
Rebecca E. Poss ◽  
...  
Keyword(s):  
Amino Acids ◽  
Energy Metabolism ◽  
Glutamate Dehydrogenase ◽  
Mitochondrial Respiration ◽  
Tca Cycle ◽  
Dependent Manner ◽  
Independent Manner ◽  
The Tca Cycle ◽  
Branched Chain ◽  
Tca Cycle Intermediates

ABSTRACTAstrocyte dysfunction is a primary factor in hepatic encephalopathy (HE) impairing neuronal activity under hyperammonemia. In particular, the early events causing ammonia-induced toxicity to astrocytes are not well understood. Using established cellular HE models, we show that mitochondria rapidly undergo fragmentation in a reversible manner upon hyperammonemia. Further, in our analyses, within a timescale of minutes, mitochondrial respiration and glycolysis were hampered, which occurred in a pH-independent manner. Using metabolomics, an accumulation of glucose and numerous amino acids, including branched chain amino acids, was observed. Metabolomic tracking of 15N-labeled ammonia showed rapid incorporation of 15N into glutamate and glutamate-derived amino acids. Downregulating human GLUD2 [encoding mitochondrial glutamate dehydrogenase 2 (GDH2)], inhibiting GDH2 activity by SIRT4 overexpression, and supplementing cells with glutamate or glutamine alleviated ammonia-induced inhibition of mitochondrial respiration. Metabolomic tracking of 13C-glutamine showed that hyperammonemia can inhibit anaplerosis of tricarboxylic acid (TCA) cycle intermediates. Contrary to its classical anaplerotic role, we show that, under hyperammonemia, GDH2 catalyzes the removal of ammonia by reductive amination of α-ketoglutarate, which efficiently and rapidly inhibits the TCA cycle. Overall, we propose a critical GDH2-dependent mechanism in HE models that helps to remove ammonia, but also impairs energy metabolism in mitochondria rapidly.

scholarly journals Phosphorylation of Arp2 is not essential for Arp2/3 complex activity in fission yeast

2018 ◽  
Author(s):  
Alexander E. Epstein ◽  
Sofia Espinoza-Sanchez ◽  
Thomas D. Pollard
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Fission Yeast ◽  
Aspartic Acid ◽  
Actin Filaments ◽  
Yeast Genome ◽  
Complex Activity ◽  
Actin Patch

AbstractLeClaire et al. presented evidence that phosphorylation of three sites on the Arp2 subunit activates Arp2/3 complex to nucleate actin filaments. We mutated the homologous residues of Arp2 (Y198, T233 and T234) in the fission yeast genome to amino acids that preclude or mimic phosphorylation. Arp2/3 complex is essential for the viability of fission yeast, yet strains unable to phosphorylate these sites grew normally. Y198F/T233A/T234A Arp2 was only nonfunctional if GFP-tagged, as observed by LeClaire et al. in Drosophila cells. Replacing both T233 and T234 with aspartic acid was lethal, suggesting that phosphorylation might be inhibitory. Nevertheless, blocking phosphorylation at these sites had the same effect as mimicking it: slowing assembly of endocytic actin patches. Mass spectrometry revealed phosphorylation at a fourth conserved Arp2 residue, Y218, but both blocking and mimicking phosphorylation of Y218 only slowed actin patch assembly slightly. Therefore, phosphorylation of Y198, T233, T234 and Y218 is not required for the activity of fission yeast Arp2/3 complex.SummaryPrevious research concluded that phosphorylation at three sites on Arp2 is necessary to activate Arp2/3 complex. Epstein et al. make genomic substitutions blocking or mimicking phosphorylation to demonstrate that phosphorylation of these three sites does not regulate Arp2/3 complex in fission yeast.

scholarly journals Construction, Growth, and Harvesting of Fission Yeast Stable Isotope Labeling by Amino Acids in Cell Culture (SILAC) Strains

2017 ◽  
Vol 2017 (6) ◽  
pp. pdb.prot091678 ◽  
Author(s):  
André Koch ◽  
Claudia C. Bicho ◽  
Weronika E. Borek ◽  
Alejandro Carpy ◽  
Boris Maček ◽  
...  
Keyword(s):  
Amino Acids ◽  
Cell Culture ◽  
Stable Isotope ◽  
Fission Yeast ◽  
Isotope Labeling ◽  
Stable Isotope Labeling

scholarly journals Fission yeast TORC1 prevents eIF2  phosphorylation in response to nitrogen and amino acids via Gcn2 kinase

2012 ◽  
Vol 125 (24) ◽  
pp. 5955-5959 ◽  
Author(s):  
N. Valbuena ◽  
A. E. Rozalen ◽  
S. Moreno
Keyword(s):  
Amino Acids ◽  
Fission Yeast ◽  
Eif2 Phosphorylation
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