Commentary, News and thoughts
Starting with a degron: N-terminal formyl-methionine of nascent bacterial proteins contributes to their proteolytic control
R. Jürgen Dohmen
In this article, the author comments on the study "Formyl-methionine as a degradation signal at the N-termini of bacterial proteins." by Piatkov et al. (Microbial Cell, 2015), discussing a novel N-terminal degradation signal (N-degron) that targets nascent proteins for degradation in Escherichia coli by a new branch of the bacterial N-end rule pathway, termed the fMet/N-end rule pathway
Elongation factor-P at the crossroads of the host-endosymbiont interface
Andrei Rajkovic1, Anne Witzky2, William Navarre3, Andrew J. Darwin4 and Michael Ibba5
Elongation factor P (EF-P) is an ancient bacterial translational factor that aids the ribosome in polymerizing oligo-prolines. EF-P structurally resembles tRNA and binds in-between the exit and peptidyl sites of the ribosome to accelerate the intrinsically slow reaction of peptidyl-prolyl bond formation. Recent studies have identified in separate organisms, two evolutionarily convergent EF-P post-translational modification systems (EPMS), split predominantly between gammaproteobacteria, and betaproteobacteria. Here, the authors highlight the recent discoveries made regarding EPMSs, with a focus on how these incomplete modification pathways shape or have been shaped by the endosymbiont-host relationship.
Feelin’ it: Differential oxidative stress sensing mediated by Cyclin C
W. Scott Moye-Rowley
Microbial cells that live exposed directly to their environmental milieu are faced with the challenge of adapting to the dynamic stress conditions that will inevitably be encountered. These stress conditions may vary over wide ranges and the most efficient responses would be tuned to produce a proportional buffering change. A mild stress would most efficiently be dealt with by a mild metabolic reprogramming that would prevent serious damage. A more severe environmental challenge would demand a more dramatic cellular compensatory response.
Subverting lysosomal function in Trypanosoma brucei
Sam Alsford
This article discusses Koh et al. (2015) "The lysosomotropic drug LeuLeu-OMe induces lysosome disruption and autophagy-independent cell death in Trypanosoma brucei (Microbial Cell 2(8): 288-298).
Entamoeba histolytica – tumor necrosis factor: a fatal attraction
Serge Ankri
This article comments on the study "In Entamoeba histolytica, a BspA family protein is required for chemotaxis toward tumour necrosis factor" by Silvestre et al. (Microbial Cell, 2015).
Toxoplasma control of host apoptosis: the art of not biting too hard the hand that feeds you
Sébastien Besteiro
Toxoplasma gondii is an obligate intracellular parasite that is able to infect a multitude of different vertebrate hosts and can survive in virtually any nucleated cell. Here, the authors discuss the article "Toxoplasma gondii inhibits cytochrome c-induced caspase activation in its host cell by interference with holo-apoptosome assembly" by Graumann et al. (2015, Microbial Cell).
A safety catch for ornithine decarboxylase degradation
Christof Taxis
Feedback inhibition is a common mechanism to adjust the activity of an enzyme in accordance with the abundance of a product. This article comments on the study "Polyamines directly promote antizyme-mediated degradation of ornithine decarboxylase by the proteasome" by Beenukumar et al. (2015), Microbial Cell.
Fancy a gene? A surprisingly complex evolutionary history of peroxiredoxins.
Alena Zíková1,2, Miroslav Oborník1,2,3 and Julius Lukeš1,2,4
In this comment, the authors discuss the article "Prokaryotic ancestry and gene fusion of a dual localized peroxiredoxin in malaria parasites" (Djuika et al., Microbial Cell 2015).
Quorum protection, growth and survival
Ian G . Macreadie
For the growth of a cell culture, one inoculates not with one cell but with a quorum of cells. This most often a requirement, not just a convenience, and most of us take this for granted without question. Here this observation is re-examined to understand why a quorum may be required to grow cells. The importance of quorums may be widespread in the aspects of microbiology they affect. It is very likely that quorums are connected with and have a large impact on the determination of Minimal Inhibitory Concentrations. It is also possible that low cell density may adversely affect cell survival, however, this is an area where even less is known. The need for a quorum might affect other aspects of microbial cell culture, cell isolation and cell preservation. Effects also extend to mammalian cell culture. Here I seek to review studies that have been documented and speculate on how the information might be utilized in the future.
Gearing up for survival – HSP-containing granules accumulate in quiescent cells and promote survival
March 6, 2016
This article comments on work published by Lee et al. (Microbial Cell, 2016), which reports that distinct granules are formed in quiescent and non-quiescent cells, which determines their respective cell fates.
Yeast screening platform identifies FDA-approved drugs that reduce Aβ oligomerization
March 3, 2016
This article comments on work published by Park et al. (Microbial Cell, 2016), which discovered a number of small molecules capable of modulating Aβ aggregation in a yeast model.
Groupthink: chromosomal clustering during transcriptional memory
November 26, 2015
In this article, the authors comment on the study "NO1 transcriptional memory leads to DNA zip code-dependent interchromosomal clustering." by Brickner et al. (Microbial Cell, 2015), discussing the importance and molecular mechanisms of chromosomal clustering during transcriptional memory.
Yeast proteinopathy models: a robust tool for deciphering the basis of neurodegeneration
November 26, 2015
Protein quality control or proteostasis is an essential determinant of basic cell health and aging. Eukaryotic cells have evolved a number of proteostatic mechanisms to ensure that proteins retain functional conformation, or are rapidly degraded when proteins misfold or self-aggregate. This article discusses the use of budding yeast as a robust proxy to study the intersection between proteostasis and neurodegenerative disease.
Starting with a degron: N-terminal formyl-methionine of nascent bacterial proteins contributes to their proteolytic control
October 4, 2015
In this article, the author comments on the study "Formyl-methionine as a degradation signal at the N-termini of bacterial proteins." by Piatkov et al. (Microbial Cell, 2015), discussing a novel N-terminal degradation signal (N-degron) that targets nascent proteins for degradation in Escherichia coli by a new branch of the bacterial N-end rule pathway, termed the fMet/N-end rule pathway
Elongation factor-P at the crossroads of the host-endosymbiont interface
September 23, 2015
Elongation factor P (EF-P) is an ancient bacterial translational factor that aids the ribosome in polymerizing oligo-prolines. EF-P structurally resembles tRNA and binds in-between the exit and peptidyl sites of the ribosome to accelerate the intrinsically slow reaction of peptidyl-prolyl bond formation. Recent studies have identified in separate organisms, two evolutionarily convergent EF-P post-translational modification systems (EPMS), split predominantly between gammaproteobacteria, and betaproteobacteria. Here, the authors highlight the recent discoveries made regarding EPMSs, with a focus on how these incomplete modification pathways shape or have been shaped by the endosymbiont-host relationship.
Feelin’ it: Differential oxidative stress sensing mediated by Cyclin C
September 6, 2015
Microbial cells that live exposed directly to their environmental milieu are faced with the challenge of adapting to the dynamic stress conditions that will inevitably be encountered. These stress conditions may vary over wide ranges and the most efficient responses would be tuned to produce a proportional buffering change. A mild stress would most efficiently be dealt with by a mild metabolic reprogramming that would prevent serious damage. A more severe environmental challenge would demand a more dramatic cellular compensatory response.
Subverting lysosomal function in Trypanosoma brucei
August 2, 2015
This article discusses Koh et al. (2015) "The lysosomotropic drug LeuLeu-OMe induces lysosome disruption and autophagy-independent cell death in Trypanosoma brucei (Microbial Cell 2(8): 288-298).
Entamoeba histolytica – tumor necrosis factor: a fatal attraction
July 6, 2015
This article comments on the study "In Entamoeba histolytica, a BspA family protein is required for chemotaxis toward tumour necrosis factor" by Silvestre et al. (Microbial Cell, 2015).
The complexities of bacterial-fungal interactions in the mammalian gastrointestinal tract
March 17, 2016
This article comments on work published by Lopez-Medina et al. (PLoS Pathog, 2015) and Fan et al. (Nat Med, 2015), which utilize an “artificial” niche, the antibiotic-treated gut with concomitant pathogenic microbe expansion, to gain insight in bacterial-fungal interactions in clinically common scenarios.