Vol. 04, 2017

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.

Post-transcriptional regulation of ribosome biogenesis in yeast

Isabelle C. Kos-Braun and Martin Koš

Microorganisms adapt to environmental changes by regulating their metabolism, and one key survival strategy is to decrease energy use during adverse conditions by halting ribosome production, with recent findings showing yeast can switch between pre-rRNA processing pathways in response to environmental shifts, adding complexity to ribosome biogenesis regulation.

Placeholder factors in ribosome biogenesis: please, pave my way

Francisco J. Espinar-Marchena, Reyes Babiano1 and Jesús de la Cruz

In ribosome synthesis, "placeholder" factors are crucial trans-acting elements that regulate the timing and assembly of ribosomal proteins, ensuring speed and accuracy in this intricate process by preventing premature interactions and guiding the proper formation of functional ribosomal subunits.

Insights from the redefinition of Helicobacter pylori lipopolysaccharide O-antigen and core-oligosaccharide domains

Hong Li1,2, Tiandi Yang3, Tingting Liao2, Aleksandra W. Debowski2,4, Hans-Olof Nilsson2, Stuart M. Haslam3, Anne Dell3, Keith A. Stubbs4, Barry J. Marshall2 and Mohammed Benghezal2,5

This article comments on work published by Li et al. (PloS Pathog, 2017), focusing on Helicobacter pylori infections. They are mostly asymptomatic but can lead to serious conditions, and H. pylori lipopolysaccharide (LPS) is crucial for colonization and persistence, making the study of its structure and biosynthesis pathway vital for understanding pathogenesis and developing treatments.

A simple microfluidic platform to study age-dependent protein abundance and localization changes in Saccharomyces cerevisiae

Margarita Cabrera1,†, Daniele Novarina1, Irina L. Rempel1, Liesbeth M. Veenhoff1, and Michael Chang1

We have developed a user-friendly microfluidic system paired with a genetic approach to enrich and study ageing mother yeast cells, enabling the monitoring of protein abundance and localization changes during the crucial first half of their replicative lifespan, leading to the discovery of novel age-dependent protein behaviors.

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.

Thiol trapping and metabolic redistribution of sulfur metabolites enable cells to overcome cysteine overload

Anup Arunrao Deshpande1,#, Muskan Bhatia1,#, Sunil Laxman2, Anand Kumar Bachhawat1

In this study, researchers investigate the mechanisms for handling cysteine overload using Saccharomyces cerevisiae, finding that overexpressing the high affinity cysteine transporter, YCT1, enables yeast cells to rapidly accumulate high levels of intracellular cysteine. The study demonstrates that cells can manage potentially toxic levels of cysteine by converting it to non-reactive thiol forms and utilizing the metabolic products for cell growth.

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Post-transcriptional regulation of ribosome biogenesis in yeast

Isabelle C. Kos-Braun and Martin Koš

Microorganisms adapt to environmental changes by regulating their metabolism, and one key survival strategy is to decrease energy use during adverse conditions by halting ribosome production, with recent findings showing yeast can switch between pre-rRNA processing pathways in response to environmental shifts, adding complexity to ribosome biogenesis regulation.

Placeholder factors in ribosome biogenesis: please, pave my way

Francisco J. Espinar-Marchena, Reyes Babiano1 and Jesús de la Cruz

In ribosome synthesis, "placeholder" factors are crucial trans-acting elements that regulate the timing and assembly of ribosomal proteins, ensuring speed and accuracy in this intricate process by preventing premature interactions and guiding the proper formation of functional ribosomal subunits.

Insights from the redefinition of Helicobacter pylori lipopolysaccharide O-antigen and core-oligosaccharide domains

Hong Li1,2, Tiandi Yang3, Tingting Liao2, Aleksandra W. Debowski2,4, Hans-Olof Nilsson2, Stuart M. Haslam3, Anne Dell3, Keith A. Stubbs4, Barry J. Marshall2 and Mohammed Benghezal2,5

This article comments on work published by Li et al. (PloS Pathog, 2017), focusing on Helicobacter pylori infections. They are mostly asymptomatic but can lead to serious conditions, and H. pylori lipopolysaccharide (LPS) is crucial for colonization and persistence, making the study of its structure and biosynthesis pathway vital for understanding pathogenesis and developing treatments.

A simple microfluidic platform to study age-dependent protein abundance and localization changes in Saccharomyces cerevisiae

Margarita Cabrera1,†, Daniele Novarina1, Irina L. Rempel1, Liesbeth M. Veenhoff1, and Michael Chang1

We have developed a user-friendly microfluidic system paired with a genetic approach to enrich and study ageing mother yeast cells, enabling the monitoring of protein abundance and localization changes during the crucial first half of their replicative lifespan, leading to the discovery of novel age-dependent protein behaviors.

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.

Thiol trapping and metabolic redistribution of sulfur metabolites enable cells to overcome cysteine overload

Anup Arunrao Deshpande1,#, Muskan Bhatia1,#, Sunil Laxman2, Anand Kumar Bachhawat1

In this study, researchers investigate the mechanisms for handling cysteine overload using Saccharomyces cerevisiae, finding that overexpressing the high affinity cysteine transporter, YCT1, enables yeast cells to rapidly accumulate high levels of intracellular cysteine. The study demonstrates that cells can manage potentially toxic levels of cysteine by converting it to non-reactive thiol forms and utilizing the metabolic products for cell growth.

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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.

Chlamydia trachomatis’ struggle to keep its host alive

March 2, 2017

This article comments on work published by Sixt et al. (Cell Host Microbe, 2016), which analyzed a CpoS-deficient mutant yielding unique insights into the nature of cell-autonomous defense responses against Chlamydia.

New insights into the function of a versatile class of membrane molecular motors from studies of Myxococcus xanthus surface (gliding) motility

March 2, 2017

This article comments on work published by Faure et al. (Nature, 2016), which deciphers force transmission at focal adhesion complexes that are involved in gliding motility in bacteria.

Advancing host-directed therapy for tuberculosis: new therapeutic insights from the Toxoplasma gondii

March 2, 2017

This article comments on work published by Koh et al. (PLoS Pathog, 2017), which uncovered that infection-induced signaling pathways suggest possibilities for the development of novel therapeutic modalities for TB that target the intracellular signaling pathways permitting the replication of Mycobacterium tuberculosis (MTB).

A multigene family encoding surface glycoproteins in Trypanosoma congolense

March 2, 2017

Trypanosoma congolense, the causative agent of the most important livestock disease in Africa, expresses specific surface proteins involved in its parasitic lifestyle. By mining the T. congolense genome database, we identified a novel family of lectin-like glycoproteins (TcoClecs).

Identification of Ftr1 and Zrt1 as iron and zinc micronutrient transceptors for activation of the PKA pathway in Saccharomyces cerevisiae

March 2, 2017

We now show that the yeast high-affinity iron transporter Ftr1 and high-affinity zinc transporter Zrt1 function as transceptors for the micronutrients iron and zinc. We show that replenishment of iron to iron-starved cells or zinc to zinc-starved cells triggers within 1-2 minutes a rapid surge in trehalase activity, a well-established PKA target.

Transceptors as a functional link of transporters and receptors

March 1, 2017

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

February 3, 2017

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

February 3, 2017

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

February 3, 2017

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

February 1, 2017

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.