Research, Research Articles

A versatile plasmid system for reconstitution and analysis of mammalian ubiquitination cascades in yeast

Rossella Avagliano Trezza1,#, Janny van den Burg1, Nico van den Oever1 and Ben Distel1,2

In this article Avagliano Trezza et al. describe a versatile vector system that allows the reconstitution of specific ubiquitination cascades in the model eukaryote Saccharomyces cerevisae (baker’s yeast) that provides a versatile tool to study complex post-translational modifications in a cellular setting.

Alcohols enhance the rate of acetic acid diffusion in S. cerevisiae : biophysical mechanisms and implications for acetic acid tolerance

Lina Lindahl1, Samuel Genheden2, Fábio Faria-Oliveira1, Stefan Allard3, Leif A. Eriksson2, Lisbeth Olsson1, Maurizio Bettiga1,4

Microbial cell factories with the ability to maintain high productivity in the presence of weak organic acids, such as acetic acid, are required in many industrial processes. This study demonstrates that the rate of acetic acid diffusion can be strongly affected by compounds that partition into the cell membrane, and highlights the need for considering interaction effects between compounds in the design of microbial processes.

Mitochondrial energy metabolism is required for lifespan extension by the spastic paraplegia-associated protein spartin

Julia Ring1, Patrick Rockenfeller1, 3, Claudia Abraham1, Jelena Tadic1, Michael Poglitsch1, Katherina Schimmel1, 4, Julia Westermayer1, Simon Schauer1, Bettina Achleitner1, Christa Schimpel1, 5, Barbara Moitzi1, Gerald N. Rechberger1, 6, Stephan J. Sigrist7, 8, Didac Carmona-Gutierrez1, Guido Kroemer9, 10, 11, 12, 13, 14, 15, Sabrina Büttner1, 16, Tobias Eisenberg1, 2, Frank Madeo1, 2

This article indicates that spartin, a protein linked to hereditary spastic paraplegias, extends yeast lifespan and reduces age-related damage by associating with mitochondria and interacting with key metabolic proteins, implicating energy metabolism in its protective role during aging.

A genome-wide screen for FTY720-sensitive mutants reveals genes required for ROS homeostasis

Kanako Hagihara1, Kanako Kinoshita1, Kouki Ishida1, Shihomi Hojo1, Yoshinori Kameoka1, Ryosuke Satoh1, Teruaki Takasaki1 and Reiko Sugiura1

Fingolimod hydrochloride (FTY720) is an immune modulator for multiple sclerosis that also induces cancer cell apoptosis through reactive oxygen species generation, with a new study using fission yeast uncovering a gene network related to ROS homeostasis as a possible mechanism of FTY720's toxicity.

Untargeted metabolomics confirms and extends the understanding of the impact of aminoimidazole carboxamide ribotide (AICAR) in the metabolic network of Salmonella enterica

Jannell V. Bazurto1, Stephen P. Dearth2, Eric D. Tague2, Shawn R. Campagna2 and Diana M. Downs1

In Salmonella enterica, aminoimidazole carboxamide ribotide (AICAR) is a purine biosynthetic intermediate and a substrate of the AICAR transformylase/IMP cyclohydrolase (PurH) enzyme. Data herein describe the use of metabolomics to identify the metabolic state of mutant strains and probe the underlying mechanisms used by AICAR to inhibit thiamine synthesis. The results obtained provide a cautionary tale of using metabolite concentrations as the only data to define the physiological state of a bacterial cell.

The cytosolic glyoxalases of Plasmodium falciparum are dispensable during asexual blood-stage development

Cletus A. Wezena1, Romy Alisch1, Alexandra Golzmann2, Linda Liedgens1, Verena Staudacher1,3, Gabriele Pradel2 and Marcel Deponte1,3

In this study the authors demonstrate that, PfGlo1 and PfcGlo2 are dispensable during asexual blood-stage development while the loss of PfcGlo2 may induce the formation of transmissible gametocytes. These combined data show that PfGlo1 and PfcGlo2 are most likely not suited as targets for selective drug development against the malaria parasite Plasmodium falciparum.

Aminoglycoside resistance profile and structural architecture of the aminoglycoside acetyltransferase AAC(6’)-Im

Clyde A. Smith1, Monolekha Bhattacharya2, Marta Toth2, Nichole K. Stewart2 and Sergei B. Vakulenko2

AAC(6')-Im, a monofunctional acetyltransferase, imparts increased resistance to certain aminoglycosides compared to its bifunctional homolog AAC(6')-Ie, with structural studies revealing differences in substrate binding that explain the discrepancies in their enzymatic activity and resistance profiles.

Cross-species complementation of bacterial- and eukaryotic-type cardiolipin synthases

Petra Gottier1, Mauro Serricchio1, Rita Vitale2, Angela Corcelli2, and Peter Bütikofer1

This article shows that cardiolipin is crucial for cellular respiration and membrane integrity, with cardiolipin synthase enzymes like TbCLS in Trypanosoma brucei being potential drug targets due to their essential role in survival. The study demonstrates TbCLS's ability to restore cardiolipin production in yeast, highlighting the specificity and potential co-localization required for cardiolipin synthesis and remodeling, and underscoring the differences between eukaryotic and prokaryotic cardiolipin synthase mechanisms.

Identification of SUMO conjugation sites in the budding yeast proteome

Miguel Esteras1, I-Chun Liu1, Ambrosius P. Snijders2, Adam Jarmuz1 and Luis Aragon1

The authors present a proteomic study that mapped SUMO acceptor lysines in budding yeast, identifying 257 potential conjugation sites, including both known and novel substrates, and providing a significant resource for future research into the functional implications of SUMOylation in yeast.

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Mitochondria-Associated Membranes (MAMs) are involved in Bax mitochondrial localization and cytochrome c release

March 15, 2019

This study investigated the role of Mitochondria-Associated Membranes (MAMs) in the regulation of apoptosis by analyzing the localization and function of the pro-apoptotic protein Bax in yeast, finding that disruption of MAMs by deletion of the MDM34 gene affects Bax's mitochondrial localization and the release of cytochrome c.

Chlamydia pneumoniae is present in the dental plaque of periodontitis patients and stimulates an inflammatory response in gingival epithelial cells

March 11, 2019

This study found that Chlamydia pneumoniae is present more frequently in the dental plaque of individuals with periodontal disease, can invade human gingival epithelial cells causing inflammatory responses, and may therefore be a contributing factor to periodontal disease and a potential indicator of risk.

Genome-wide analysis of yeast expression data based on a priori generated co-regulation cliques

January 22, 2019

The study demonstrates the use of predefined genome-wide expression cliques, derived from extensive microarray data, to effectively analyze and visualize the complete gene expression response across various cellular conditions in yeast.

A humanized yeast-based toolkit for monitoring phosphatidylinositol 3-kinase activity at both single cell and population levels

November 12, 2018

In this study, a humanized yeast system for functional studies on higher eukaryotic Phosphatidylinositol 3-kinase (PI3K) was developed by restricting PI3K activity in yeast to specific plasma membrane microdomains, utilizing engineered reporters to monitor activity at a single-cell level and employing novel tools to study the performance of yeast plasma membrane (PM) microdomain-directed PI3K, revealing location-specific effects on yeast growth and endocytosis.

A chemical genetic screen reveals a role for proteostasis in capsule and biofilm formation by Cryptococcus neoformans

October 31, 2018

This study demonstrates that the bipolar disorder drug lithium inhibits the formation of key virulence factors, biofilm, and polysaccharide capsule, in Cryptococcus neoformans by dysregulating the ubiquitin/proteasome system, shedding light on the impact of lithium and providing insights into potential alternative pharmaceutical approaches for combating this fungal pathogen.

Nutritional and meiotic induction of transiently heritable stress resistant states in budding yeast

October 29, 2018

This study demonstrates that transient exposures to environmental stresses induce persistent states of elevated stress resistance in yeast cells, termed cellular memory, suggesting a form of epigenetic inheritance, and shows that this phenomenon occurs not only in meiotically produced spores but also in haploid cells subjected to glucose withdrawal, adding new insights into the developmentally and nutritionally induced cellular memory.

Specific mutations in the permease domain of septal protein SepJ differentially affect functions related to multicellularity in the filamentous cyanobacterium Anabaena

October 16, 2018

In this study, the multifunctional roles of the SepJ protein in the multicellular function of the Anabaena filament were investigated, revealing that specific amino acids and stretches within the protein are essential for the formation of long filaments, heterocyst differentiation, and intercellular communication, shedding light on the structure and diverse functions of SepJ in the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120.

Trehalose-6-phosphate promotes fermentation and glucose repression in Saccharomyces cerevisiae

October 1, 2018

This study examined the capability of trehalose-6-phosphate synthase (TPS1) homologues from various species to complement the phenotypic defects of a Saccharomyces cerevisiae tps1 mutant, resulting in the classification of complementation into different groups based on metabolic patterns and fermentation capacity, shedding light on the role of TPS1 and trehalose-6-phosphate (T6P) as critical factors in sugar fermentation and glucose repression.

Single telomere length analysis in Ustilago maydis, a high-resolution tool for examining fungal telomere length distribution and C-strand 5’-end processing

August 7, 2018

This article introduces the development of single telomere length analysis (STELA) for Ustilago maydis, a basidiomycete fungus, enabling the precise measurement of telomere lengths and distributions. The study demonstrates STELA's utility in revealing the existence of relatively short telomeres in wild-type cells, preferential loss of long telomeres in a mutant defective in telomere replication, and the characterization of telomere C-strand 5’ ends, highlighting U. maydis as a strong model for telomere research.

Temporal analysis of the autophagic and apoptotic phenotypes in Leishmania parasites

August 1, 2018

This article details a comprehensive analysis of miltefosine-induced cell death and autophagy in Leishmania major, providing criteria for clear identification of apoptotic and autophagic cells, demonstrating the sequential nature of autophagy followed by apoptosis in nutrient-deprived conditions, and cautioning against using the generic kinase inhibitor staurosporine as a Leishmania apoptosis inducer, with the aim of improving the understanding of these processes and their targeting for new anti-leishmanial drugs.

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