Vol. 04, 2017

Transceptors as a functional link of transporters and receptors

George Diallinas

A relative newcomer in environment sensing are the so called transceptors, membrane proteins that possess both solute transport and receptor-like signaling activities. Now, the transceptor concept is further enlarged to include micronutrient sensing via the iron and zinc high-affinity transporters of Saccharomyces cerevisiae.

S. pombe placed on the prion map

Jacqueline Hayles

This article comments on work published by Sideri et al. (Microbial Cell, 2017), which identified the Ctr4 prion in S. pombe.

Balanced CoQ6 biosynthesis is required for lifespan and mitophagy in yeast

Isabel González-Mariscal, Aléjandro Martín-Montalvo, Cristina Ojeda-González, Adolfo Rodríguez-Eguren, Purificación Gutiérrez-Ríos, Plácido Navas, and Carlos Santos-Ocaña

In brief, we show that, in yeast, Ptc7 modulates the adaptation to respiratory metabolism by dephosphorylating Coq7 to supply newly synthesized CoQ6, and by activating mitophagy to remove defective mitochondria at stationary phase, guaranteeing a proper CLS in yeast.

Breaking the bilayer: OMV formation during environmental transitions

Katherine E. Bonnington, Meta J. Kuehn

This article comments on work published by Bonnington & Kuehn (MBio, 2016), which shows how gram-negative bacteria maintain the barrier properties of the outer membrane (OM) in a wide array of physiological conditions despite their inability to degrade lipopolysaccharide (LPS) and protein material present in the outer leaflet of the OM.

Mutational analysis of fructose-1,6-bis-phosphatase FBP1 indicates partially independent functions in gluconeogenesis and sensitivity to genotoxic stress

Ali Ghanem, Ana Kitanovic, Jinda Holzwarth, Stefan Wölfl

Our results support predicted vital roles of several fructose-1,6-bisphosphatase residues for enzymatic activity and led to the identification of residues indispensable for the MMS-sensitizing effect. Despite an overlap between these two properties, careful analysis revealed two mutations, Asn75 and His324, which decouple the enzymatic activity and the MMS-sensitizing effect, indicating two distinctive biological activities linked in this key gluconeogenesis enzyme.

The tug-of-war over MTOR in Legionella infections

Stanimir S. Ivanov

This article comments on work published by Abshire et al (PLoS Pathog, 2016), which uncovered that the host metabolic checkpoint kinase Mechanistic target of rapamycin (MTOR) is a central regulator of the pathogen niche expansion program.

A new role for Holliday junction resolvase Yen1 in processing DNA replication intermediates exposes Dna2 as an accessory replicative helicase

Benoît Falquet1,2 and Ulrich Rass

This article comments on work published by Ölmezer et al. (Nat Commun, 2016), which revealed a new function of Yen1, distinct from its previously known role as a Holliday junction resolvase, mediating the removal of branched HR intermediates.

The copper transport-associated protein Ctr4 can form prion-like epigenetic determinants in Schizosaccharomyces pombe

Theodora Sideri1, Yoko Yashiroda2, David A. Ellis1, María Rodríguez-López1, Minoru Yoshida2, Mick F. Tuite3 & Jürg Bähler1

Ctr4 exhibits multiple features diagnostic of other fungal prions and is the first example of a prion in fission yeast. These findings suggest that transmissible protein-based determinants of traits may be more widespread among fungi.

Using microbes as a key tool to unravel the mechanism of autophagy and the functions of the ATG proteins

Mario Mauthe1,2 and Fulvio Reggiori1,2

Microbes have served to discover and characterize unconventional functions of the ATG proteins, which are uncoupled from their role in autophagy. In our recent study, we have taken advantage of viruses as a screening tool to determine the extent of the unconventional functions of the ATG proteome and characterize one of them.

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Inhibitors of glycosomal protein import provide new leads against trypanosomiasis

Vishal C. Kalel1, Leonidas Emmanouilidis2,3, Maciej Dawidowski2,3,4, Wolfgang Schliebs1, Michael Sattler2,3, Grzegorz M. Popowicz2,3, Ralf Erdmann1

This article comments on work published by Dawidowski et al. (Science, 2017), which provides the grounds for further development of the glycosome inhibitors into clinical candidates and validates the parasite protein-protein interactions as drug targets.

Impact of the host on Toxoplasma stage differentiation

Carsten G.K. Lüder1 and Taibur Rahman1

This review summarizes how Toxoplasma gondii transitions from an acute to a chronic infection in warm-blooded animals and humans through a developmental switch influenced by host cell physiology, which determines parasite persistence mainly in neural and muscular tissues.

Chlamydia and mitochondria – an unfragmented relationship

Suvagata Roy Chowdhury1 and Thomas Rudel1

This article comments on work published by Chowdhury et al (J Cell Biol, 2017), which demonstrated that Chlamydia infection induces and requires an upregulation of the host miRNA, miR-30c-5p (miR-30c) to ameliorate infection induced stress on the host mitochondrial architecture and hinders induction of apoptosis.

Integrative modules for efficient genome engineering in yeast

Triana Amen1 and Daniel Kaganovich1

The study introduces a set of vectors with integrative modules designed for effective genome integration into standard marker loci of Saccharomyces cerevisiae, enabling precise expression levels using various promoters and demonstrating the capability of stable multi-gene integration, which is useful for tasks like multi-color cellular imaging and metabolic engineering.

The neuroprotective steroid progesterone promotes mitochondrial uncoupling, reduces cytosolic calcium and augments stress resistance in yeast cells

Slaven Stekovic1,*, Christoph Ruckenstuhl1,*, Philipp Royer1, Christof Winkler-Hermaden1, Didac Carmona-Gutierrez1, Kai-Uwe Fröhlich1, Guido Kroemer3-8, and Frank Madeo1,2

Progesterone, known for its role in the reproductive system, also acts as a neurosteroid and has been suggested to aid recovery from traumatic brain injury; a study using yeast models shows that progesterone can protect against apoptosis, reduce oxidative stress and calcium spikes, and increase mitochondrial function, independent of traditional progesterone receptors or calcium transporters.

Protein aggregation triggers a declining libido in elder yeasts that still have a lust for life

Fabrice Caudron

This article comments on work published by Schlissel et al (Science 2017), showing that aging in yeast does not lead to the expected loss of heterochromatin silencing due to Sir2 inactivity, but rather to reduced mating pheromone sensitivity caused by the aggregation of the RNA-binding protein Whi3, which can be reversed by eliminating Whi3's polyglutamine domain.

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The tug-of-war over MTOR in Legionella infections

Stanimir S. Ivanov

This article comments on work published by Abshire et al (PLoS Pathog, 2016), which uncovered that the host metabolic checkpoint kinase Mechanistic target of rapamycin (MTOR) is a central regulator of the pathogen niche expansion program.

A new role for Holliday junction resolvase Yen1 in processing DNA replication intermediates exposes Dna2 as an accessory replicative helicase

Benoît Falquet1,2 and Ulrich Rass

This article comments on work published by Ölmezer et al. (Nat Commun, 2016), which revealed a new function of Yen1, distinct from its previously known role as a Holliday junction resolvase, mediating the removal of branched HR intermediates.

Toxin-mediated gene regulatory mechanism in Staphylococcus aureus

Hwang-Soo Joo and Michael Otto

This article comments on work published by Joo et al. (MBio, 2016), which describes the first molecular regulatory mechanism exerted by an S. aureus toxin, setting a paradigmatic example of how S. aureus toxins may influence cell functions to adjust them to times of toxin production.

Uncovering the hidden: complexity and strategies for diagnosing latent tuberculosis

Mario Alberto Flores-Valdez

This editorial postulates that advanced proteomic and transcriptomic techniques are evolving and may enhance the detection of latent tuberculosis, thereby distinguishing true M. tuberculosis infections from other conditions, which is vital for controlling potential reactivation and transmission.

The Yin & Yang of Mitochondrial Architecture – Interplay of MICOS and F1Fo-ATP synthase in cristae formation

Heike Rampelt1 and Martin van der Laan2

This Editorial posits that mitochondrial cristae architecture is shaped by the interplay of MICOS and ATP synthase, with a recent study illuminating their roles in cristae formation and maintenance.

When a ribosomal protein grows up – the ribosome assembly path of Rps3

Brigitte Pertschy

This article comments on two papers by Mitterer et al., which followed yeast protein Rps3, highlighting the sophisticated mechanisms for protein protection, nuclear transport, and integration into pre-ribosomal particles for final assembly with 40S subunits.

Staphylococcus aureus type I signal peptidase: essential or not essential, that’s the question

Wouter L.W. Hazenbos1, Elizabeth Skippington2 and Man-Wah Tan1

This article comments on work published by Morisaki et al. (mBio, 2016), which characterized a novel ABC transporter. This transporter apparently compensates for SpsB’s essential function by mediating alternative cleavage of a subset of proteins at a site distinct from the SpsB-cleavage site, leading to SpsB-independent secretion.

Transceptors as a functional link of transporters and receptors

George Diallinas

A relative newcomer in environment sensing are the so called transceptors, membrane proteins that possess both solute transport and receptor-like signaling activities. Now, the transceptor concept is further enlarged to include micronutrient sensing via the iron and zinc high-affinity transporters of Saccharomyces cerevisiae.

S. pombe placed on the prion map

Jacqueline Hayles

This article comments on work published by Sideri et al. (Microbial Cell, 2017), which identified the Ctr4 prion in S. pombe.

Using microbes as a key tool to unravel the mechanism of autophagy and the functions of the ATG proteins

Mario Mauthe1,2 and Fulvio Reggiori1,2

Microbes have served to discover and characterize unconventional functions of the ATG proteins, which are uncoupled from their role in autophagy. In our recent study, we have taken advantage of viruses as a screening tool to determine the extent of the unconventional functions of the ATG proteome and characterize one of them.

Identification of SUMO conjugation sites in the budding yeast proteome

October 2, 2017

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.

Ydj1 governs fungal morphogenesis and stress response, and facilitates mitochondrial protein import via Mas1 and Mas2

October 2, 2017

The authors descibe the role of the Hsp40 chaperone Ydj1 in Candida albicans, noting its localization to the cytosol and mitochondrial membrane, its necessity for stress responses and filamentation, and its involvement in a protein interaction network related to co-chaperones, filamentation regulators, and mitochondrial processing peptidases, with a particular focus on the impact of Ydj1 on mitochondrial morphology, function, and the import of precursor proteins.

Yeast for virus research

September 18, 2017

This article summarizes the use of budding yeast (Saccharomyces cerevisiae) and fission yeast (Schizosaccharomyces pombe) in virus research, highlighting their advantages for studying viral replication, interaction with host cells, and fundamental cellular processes affected by viruses, while discussing their potential in analyzing small viral genomes and facilitating the discovery of antiviral drugs.

Macrophages as drivers of an opportunistic infection

September 13, 2017

This article comments on work published by Mesureur et al. (PloS Pathog, 2017), which shows that macrophages are essential for proliferation of B. cenocepacia in the host. This suggests a new paradigm for Bcc infections and urges the development of novel anti-infectious therapies to efficiently disarm these intrinsically antibiotic resistant facultative intracellular pathogens.

Farnesol inhibits translation to limit growth and filamentation in C. albicans and S. cerevisiae

September 4, 2017

Farnesol, a quorum-sensing molecule, inhibits the switch from yeast to filamentous growth in Candida albicans by impeding translation initiation, differing from fusel alcohols that affect the initiation factor eIF2B, as it disrupts mRNA interaction with the ribosome and prevents preinitiation complex formation.

A yeast model for the mechanism of the Epstein-Barr virus immune evasion identifies a new therapeutic target to interfere with the virus stealthiness

August 31, 2017

This article comments on a publication by Lista et al. (Nature Communications, 2017) that uncovered the role of the host cell nucleolin (NCL) in EBNA1 self-limitation of expression via a direct interaction of this protein with G-quadruplexes (G4) formed in GAr-encoding sequence of EBNA1 mRNA.

Exacerbating and reversing lysosomal storage diseases: from yeast to humans

August 25, 2017

This article summarizes the use of yeast models in advancing our understanding of lysosomal storage diseases (LSDs), where they have been instrumental in researching LSD mechanisms, screening for therapeutic compounds, and exploring genetic and gene-environment interactions relevant to diseases like Batten disease, cystinosis, and Niemann-Pick type C disease, as well as their connection to broader health issues such as viral infections and obesity.

Live fast, die fast principle in a single cell of fission yeast

August 13, 2017

This article comments on a recent study (Nakaoka and Wakamoto, PLoS Biol, 2017), which developed a microfluidics-based platform to track multiple single cell lineages until death.

The Yin & Yang of Mitochondrial Architecture – Interplay of MICOS and F1Fo-ATP synthase in cristae formation

August 6, 2017

This Editorial posits that mitochondrial cristae architecture is shaped by the interplay of MICOS and ATP synthase, with a recent study illuminating their roles in cristae formation and maintenance.

Out with the old: Hsp90 finds amino acid residue more useful than co-chaperone protein

August 1, 2017

This article comments on work published by Zuehlke et al (Nat Commun, 2017), which demonstrates that the function of one co-chaperone in yeast is replaced by posttranslational modification (PTM) of a single amino acid within Hsp90 in higher eukaryotes.