Research, Research Articles
Cell wall dynamics modulate acetic acid-induced apoptotic cell death of Saccharomyces cerevisiae
António Rego#, Ana Marta Duarte#, Flávio Azevedo#, Maria João Sousa, Manuela Côrte-Real and Susana R. Chaves
This work characterizes the involvement of MAPK signaling pathways in cell death induced by acetic acid in Saccharomyces cerevisiae.
Extracellular calcium triggers unique transcriptional programs and modulates staurosporine-induced cell death in Neurospora crassa
A. Pedro Gonçalves1,2, João Monteiro2, Chiara Lucchi2, David J. Kowbel3, J. Miguel Cordeiro1,4, Paulo Correia-de-Sá1,4, Daniel J. Rigden5, N. Louise Glass3, Arnaldo Videira1,2
The results presented here reveal that in Neurospora crassa, extracellular Ca2+ modulates cell death and the transcriptional alterations induced by staurosporine, and lead to the identification of two novel putative Ca2+-binding proteins, encoded by the NCU08524 and NCU06607 genes.
Multiple metabolic requirements for size homeostasis and initiation of division in Saccharomyces cerevisiae
Shivatheja Soma, Kailu Yang, Maria I. Morales and Michael Polymenis
This article reveals an unexpected diversity in the G1 cell cycle phenotypes of metabolic and biosynthetic Saccharomyces cerevisiae mutants, suggesting that growth requirements for cell division are multiple, distinct and imposed throughout the G1 phase of the cell cycle.
Exogenous addition of histidine reduces copper availability in the yeast Saccharomyces cerevisiae
Daisuke Watanabe, Rie Kikushima, Miho Aitoku, Akira Nishimura, Iwao Ohtsu, Ryo Nasuno, and Hiroshi Takagi
The herein presented results indicate that in Saccharomyces cerevisiae, histidine cytotoxicity is associated with low copper availability inside cells, not with impaired copper uptake. Furthermore, it suggests that histidine cytotoxicity is involved in deficiency of mitochondrial copper.
Effect of paraquat-induced oxidative stress on gene expression and aging of the filamentous ascomycete Podospora anserina
Matthias Wiemer and Heinz D. Osiewacz
In this article, paraquat is used to experimentally induce strong cellular oxidative stress in Podospora anserina wild-type cultures of different age, finding that this treatment has profound effects on gene expression, growth and lifespan.
Heat shock protein 90 and calcineurin pathway inhibitors enhance the efficacy of triazoles against Scedosporium prolificans via induction of apoptosis
Fazal Shirazi and Dimitrios P. Kontoyiannis
This article reports for the first time that posaconazole (PCZ) or itraconazolein (ICZ) in combination with the calcineurin inhibitor tacrolimus or the Hsp90 inhibitor 17-demethoxy-17-(2-propenylamino) geldanamycin renders S. prolificans exquisitely sensitive to PCZ or ICZ via apoptosis.
At neutral pH the chronological lifespan of Hansenula polymorpha increases upon enhancing the carbon source concentrations
Adam Kawałek and Ida J. van der Klei
The data presented in this work indicate that in H. polymorpha at neutral pH the chronological lifespan invariably extends upon increasing the carbon source concentration.
Salt stress causes cell wall damage in yeast cells lacking mitochondrial DNA
Qiuqiang Gao1, Liang-Chun Liou2, Qun Ren2, Xiaoming Bao3 and Zhaojie Zhang2
In this work, the authors report that salt stress causes cell wall damage in yeast cells lacking mitochondrial DNA (ρ0) and that this damage is related to elevated levels of SCW11 and salt stress-induced reactive oxygen species.
Protein oxidation in the intermembrane space of mitochondria is substrate-specific rather than general
Valentina Peleh1, Jan Riemer2, Andrew Dancis3 and Johannes M. Herrmann1
In this work, the authors suggest that in Saccharomyces cerevisiae, the Mia40-dependent oxidation of proteins in the intermembrane space only takes place in specific proteins and presumably relies on the presence of Mia40-binding sites.
Impact of histone H4K16 acetylation on the meiotic recombination checkpoint in Saccharomyces cerevisiae
December 4, 2016
In meiotic cells, the pachytene checkpoint or meiotic recombination checkpoint is a surveillance mechanism that monitors critical processes, such as recombination and chromosome synapsis, which are essential for proper distribution of chromosomes to the meiotic progeny. We report here that Sas2-mediated acetylation of histone H4 at lysine 16 (H4K16ac) modulates meiotic checkpoint activity in response to synaptonemal complex defects. Our results reveal that proper levels of H4K16ac orchestrate this meiotic quality control mechanism and that Sir2 impinges on additional targets to fully activate the checkpoint.
The transcription factors ADR1 or CAT8 are required for RTG pathway activation and evasion from yeast acetic acid-induced programmed cell death in raffinose
December 2, 2016
Yeast Saccharomyces cerevisiae grown on glucose undergoes programmed cell death (PCD) induced by acetic acid (AA-PCD), but evades PCD when grown in raffinose. This is due to concomitant relief of carbon catabolite repression (CCR) and activation of mitochondrial retrograde signaling. In this work, we investigated the relationships between the RTG and CCR pathways in the modulation of AA-PCD sensitivity under glucose repression or de-repression conditions. Our data show that simultaneous mitochondrial retrograde pathway activation and SNF1-dependent relief of CCR have a key role in central carbon metabolism reprogramming which modulates the yeast acetic acid-stress response.
The ubiquitin-conjugating enzyme, Ubc1, indirectly regulates SNF1 kinase activity via Forkhead-dependent transcription
November 5, 2016
The SNF1 kinase class of serine/threonine kinases, which includes the AMP-dependent protein kinase (AMPK) in other systems, are of widespread interest because of their important roles in glucose homeostasis, stress resistance, and aging. Our goal was to identify discrete ubiquitin-conjugating enzymes that are involved in SNF1 kinase activity in response to glucose levels and anticipated revealing those which are involved in Snf1-Ub attachment. Here, we report that the cell cycle and stress-related E2, Ubc1, indirectly affects SNF1 kinase activity not through stability, but through upstream events.
Phylogenetic profiles of all membrane transport proteins of the malaria parasite highlight new drug targets
August 30, 2016
In order to combat the on-going malaria epidemic, discovery of new drug targets remains vital. Proteins that are essential to survival and specific to malaria parasites are key candidates. Here, we present a comprehensive orthology assignment of all Plasmodium falciparum putative membrane transport proteins and provide a detailed overview of the associated essential gene functions obtained through experimental genetics studies in human and murine model parasites.
VDAC regulates AAC-mediated apoptosis and cytochrome c release in yeast
August 25, 2016
Mitochondrial outer membrane permeabilization is a key event in apoptosis processes leading to the release of lethal factors. In this study, we sought to determine whether Por1p functionally interacts with ADP/ATP carrier (AAC) proteins, as well as its contribution to cytochrome c release and yeast apoptosis induced by acetic acid treatment. Our data indicate that Por1p may regulate cell survival by acting as a negative regulator of AAC proteins in the apoptotic cascade.
Attenuation of polyglutamine-induced toxicity by enhancement of mitochondrial OXPHOS in yeast and fly models of aging
July 26, 2016
Defects in mitochondrial biogenesis and function are common in many neurodegenerative disorders, including Huntington’s disease (HD). We could shown that enhancement of mitochondrial biogenesis protects against neurodegeneration in HD yeast and fly models. Our results suggest that therapeutic interventions aiming at the enhancement of mitochondrial respiration and OXPHOS could reduce polyQ toxicity and delay disease onset.
Cox1 mutation abrogates need for Cox23 in cytochrome c oxidase biogenesis
June 30, 2016
Cox23 is a known conserved assembly factor for cytochrome c oxidase, although its role in cytochrome c oxidase (CcO) biogenesis remains unresolved. To gain additional insights into its role, we isolated spontaneous suppressors of the respiratory growth defect in cox23∆ yeast cells. In this report, we describe the isolation of a robust suppressor of the respiratory defect in cox23∆ cells that mapped to the mitochondrial-encoded Cox1 subunit.
Increased spontaneous recombination in RNase H2-deficient cells arises from multiple contiguous rNMPs and not from single rNMP residues incorporated by DNA polymerase epsilon
May 15, 2016
Ribonucleotides (rNMPs) can become embedded in DNA from insertion by DNA polymerases, failure to remove Okazaki fragment primers, R-loops that can prime replication, and RNA/cDNA-mediated recombination. We report here that recombination is not stimulated by rNMPs incorporated by the replicative polymerase epsilon. Instead, recombination seems to be stimulated by multiple contiguous rNMPs, which may arise from R-loops or replication priming events.
Construction and evaluation of yeast expression networks by database-guided predictions
May 10, 2016
DNA-Microarrays are powerful tools to obtain expression data on the genome-wide scale. We set out to define a way to cluster microarray data according to their expressional relationship and to obtain information on the significance of this clustering approach.
Optogenetic monitoring identifies phosphatidylthreonine-regulated calcium homeostasis in Toxoplasma gondii
May 1, 2016
Toxoplasma gondii is an obligate intracellular parasite, which inflicts acute as well as chronic infections in a wide range of warm-blooded vertebrates. Using an optogenetic sensor to monitor subcellular calcium in this model intracellular pathogen we found a novel regulatory function of phosphatidylthreonine in calcium signaling.