Research, Research Reports
Formaldehyde fixation is detrimental to actin cables in glucose-depleted S. cerevisiae cells
Pavla Vasicova1,#, Mark Rinnerthaler2, Danusa Haskova1, Lenka Novakova1, Ivana Malcova1, Michael Breitenbach2, Jiri Hasek1
Actin filaments form cortical patches and emanating cables in fermenting cells of Saccharomyces cerevisiae. We assume that stability of actin cables reflects the metabolic status of the cell. Based on comparison of live and formaldehyde-fixed cells, our data suggest that formaldehyde affects respiration before fixation and this uneven signaling results in destabilization of actin cables in glucose-deprived cells.
Insights into dynamin-associated disorders through analysis of equivalent mutations in the yeast dynamin Vps1
Laila Moustaq, Iwona I. Smaczynska-de Rooij, Sarah E. Palmer, Christopher J. Marklew, Kathryn R. Ayscough
The dynamins represent a superfamily of proteins that have been shown to function in a wide range of membrane fusion and fission events. An increasing number of mutations in the human classical dynamins, Dyn-1 and Dyn-2 has been reported, with diseases caused by these changes ranging from Charcot-Marie-Tooth disorder to epileptic encephalopathies. This study aimed to use the dynamin-like protein Vps1 of Saccharomyces cerevisiae as a model to gain insights into the mechanistic defects caused by specific dynamin mutations considered to underlie a number of diseases.
Genomic saturation mutagenesis and polygenic analysis identify novel yeast genes affecting ethyl acetate production, a non-selectable polygenic trait
Tom Den Abt1,2, Ben Souffriau1,2, Maria R. Foulquié-Moreno1,2, Jorge Duitama3, and Johan M. Thevelein1,2
Isolation of mutants in populations of microorganisms has been a valuable tool in experimental genetics for decades. The main disadvantage, however, is the inability of isolating mutants in non-selectable polygenic traits. Our study shows that genomic saturation mutagenesis combined with complex trait polygenic analysis could be used successfully to identify causative alleles underlying many non-selectable, polygenic traits in small collections of haploid strains with multiple induced mutations.
Differentiated cytoplasmic granule formation in quiescent and non-quiescent cells upon chronological aging
Hsin-Yi Lee1,3,†, Kuo-Yu Cheng2,3,†, Jung-Chi Chao3 and Jun-Yi Leu3
Stationary phase cultures represent a complicated cell population comprising at least two different cell types, quiescent (Q) and non-quiescent (NQ) cells. The authors show that the cell fate of NQ cells is largely irreversible even if they are allowed to reenter mitosis. Their results reveal that the formation of different granule structures may represent the early stage of cell type differentiation in yeast stationary phase cultures.
Towards understanding the gliotoxin detoxification mechanism: in vivo thiomethylation protects yeast from gliotoxin cytotoxicity
Elizabeth B. Smith, Stephen K. Dolan, David A. Fitzpatrick, Sean Doyle and Gary W. Jones
Gliotoxin is a mycotoxin produced by some species of ascomycete fungi including the opportunistic human pathogen Aspergillus fumigatus. In order to produce gliotoxin the host organism needs to have evolved a self-protection mechanism. The authors demonstrate that the activity of a novel thiomethyltransferase is requiered for protection against exogenous gliotoxin and provide implications for understanding the evolution of gliotoxin self-protection mechanisms.
Mitochondrial proteomics of the acetic acid – induced programmed cell death response in a highly tolerant Zygosaccharomyces bailii – derived hybrid strain
Joana F Guerreiro1, Belém Sampaio-Marques2,3, Renata Soares4, Ana Varela Coelho4, Cecília Leão2,3, Paula Ludovico2,3, Isabel Sá-Correia1
Very high concentrations of acetic acid at low pH induce programmed cell death (PCD) in both the experimental model Saccharomyces cerevisiae and in Zygosaccharomyces bailii, the latter being considered the most problematic acidic food spoilage yeast due to its remarkable intrinsic resistance to this food preservative. This study offers insights into the mechanisms involved in acetic acid - induced PCD in the Z. bailii-derived hybrid strain ISA1307 by analyzing the yeast mitochondrial protein expression profile of cells challenged by acetic acid.
The transcriptional repressor Sum1p counteracts Sir2p in regulation of the actin cytoskeleton, mitochondrial quality control and replicative lifespan in Saccharomyces cerevisiae
Ryo Higuchi-Sanabria1, Jason D. Vevea1,3, Joseph K. Charalel1,4, Maria L. Sapar5, Liza A. Pon1,2
Increasing the stability or dynamics of the actin cytoskeleton can extend lifespan in C. elegans and S. cerevisiae. Actin cables of budding yeast, bundles of actin filaments that mediate cargo transport, affect lifespan control through effects on mitochondrial quality control. Here, we report that Sum1p and Sir2p inversely regulate actin and mitochondrial maintenance, as well as lifespan.
Inhibition of Aβ42 oligomerization in yeast by a PICALM ortholog and certain FDA approved drugs
Sei-Kyoung Park1, Kiira Ratia2, Mariam Ba1, Maria Valencik1 and Susan W. Liebman1,3
The formation of small Aβ42 oligomers has been implicated as a toxic species in Alzheimer disease (AD). Here, we show that the mechanism of the PICALM, human AD risk factor, is likely to reduce the level of Aβ42 oligomers in cells. We screened FDA-approved drugs to identify candidates that prevent the formation of Aβ42 small oligomers using the yeast Aβ42-RF reporter system. We also showed that each of the drug hits counteract yeast and mammalian cell toxicity associated with Aβ42 small aggregates.
Global translational impacts of the loss of the tRNA modification t6A in yeast
Patrick C. Thiaville1,2,3,4, Rachel Legendre4, Diego Rojas-Benítez5, Agnès Baudin-Baillieu4, Isabelle Hatin4, Guilhem Chalancon6, Alvaro Glavic5, Olivier Namy4, Valérie de Crécy-Lagard1,3
The universal tRNA modification t6A is found at position 37 of nearly all tRNAs decoding ANN codons. Analysis of codon occupancy rates suggests that one of the major roles of t6A is to homogenize the process of elongation by slowing the elongation rate at codons decoded by high abundance tRNAs and I34:C3 pairs while increasing the elongation rate of rare tRNAs and G34:U3 pairs. This work reveals that the consequences of t6A absence are complex and multilayered and has set the stage to elucidate the molecular basis of the observed phenotypes.
A novel BR-SMAD is required for larval development in barber’s pole worm Haemonchus contortus
December 23, 2020
The herein presented results show a BMP-like receptor-regulated SMAD in Haemonchus contortus that is required for larval differentiation and underscore an adaptive functional repurposing of BMP-signaling in parasitic worms.
Nutrient sensing and cAMP signaling in yeast: G-protein coupled receptor versus transceptor activation of PKA
October 12, 2020
The herein presented work supports a model, in which nutrient transceptors are evolutionary ancestors of GPCRs, employing a more primitive direct signaling mechanism compared to the indirect cAMP second-messenger signaling mechanism used by GPCRs for activation of PKA.
Novobiocin inhibits membrane synthesis and vacuole formation of Enterococcus faecalis protoplasts
August 10, 2020
In this study Tsuchikado et al. show that DNA replication is crucial for plasma membrane biosynthesis and vacuole formation in Enterococcus faecalis protoplasts. Novobiocin inhibits DNA replication, blocking cell enlargement and vacuole formation. Extended treatment prevents re-enlargement after removal.
Variants of the human RAD52 gene confer defects in ionizing radiation resistance and homologous recombination repair in budding yeast
July 20, 2020
RAD52 is a key protein in DNA repair and suppresses DNA damage in yeast; however, certain variants affecting BRCA2 mutations fail to correct HRR defects. This suggests that HsRAD52 aids multiple DNA repair mechanisms and could be targeted for use in treating BRCA2-deficient cancers.
Systematic analysis of nuclear gene function in respiratory growth and expression of the mitochondrial genome in S. cerevisiae
June 30, 2020
Using yeast Saccharomyces cerevisiae, the authors identified 254 nuclear genes essential for respiratory growth and 12 required for viability without mtDNA. They also found 176 genes involved in mitochondrial protein synthesis and mtDNA maintenance, offering a comprehensive view of the processes supporting oxidative phosphorylation.
Histone H3E73Q and H4E53A mutations cause recombinogenic DNA damage
April 24, 2020
This study reveals that conserved residues H3E73 and H4E53 in histones H3 and H4 play a crucial role in maintaining genome stability. Mutations at these sites increase recombinogenic DNA damage, likely due to replication-associated issues rather than transcriptional activity, highlighting their importance in DNA damage prevention and repair.
Sulforaphane alters the acidification of the yeast vacuole
March 20, 2020
This study identifies vacuolar pH regulation as a key factor in sulforaphane (SFN) sensitivity, showing that SFN-induced cell death in yeast - and potentially in human cancer cells - is linked to its ability to raise vacuolar or lysosomal pH.
Broad-spectrum antifungal activities and mechanism of drimane sesquiterpenoids
March 12, 2020
This study identifies (-)-drimenol as a potent broad-spectrum antifungal agent effective against multiple pathogenic fungi, including drug-resistant strains, and reveals its mechanism of action involves disruption of fungal membranes and targeting Crk1-related pathways, with potential for structural optimization to enhance efficacy.
Stable and destabilized GFP reporters to monitor calcineurin activity in Saccharomyces cerevisiae
February 5, 2020
This study introduces GFP-based transcriptional reporters driven by a calcineurin-dependent response element, enabling real-time monitoring of calcineurin activity in live yeast cells for studying stress responses, aging, and antifungal drug screening.
The euchromatic histone mark H3K36me3 preserves heterochromatin through sequestration of an acetyltransferase complex in fission yeast
January 3, 2020
This study reveals that the loss of heterochromatin silencing in Set2-deficient cells is due to unrestrained Mst2C activity, highlighting the need for spatially restricted chromatin-modifying enzymes to maintain distinct chromatin states.