scholarly journals Mutations of the YidC Insertase alleviate stress from σM-dependent membrane protein overproduction in Bacillus subtilis

2019 ◽  
Author(s):  
Heng Zhao ◽  
Ankita J. Sachla ◽  
John D. Helmann
Keyword(s):  
Oxidative Stress ◽  
Cell Wall ◽  
Bacillus Subtilis ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Substrate Binding ◽  
Single Amino Acid ◽  
Cell Wall Synthesis ◽  
Intrinsic Resistance ◽  
Σ Factor

AbstractIn Bacillus subtilis, the extracytoplasmic function σ factor σM regulates cell wall synthesis and is critical for intrinsic resistance to cell wall targeting antibiotics. The anti-σ factors YhdL and YhdK form a complex that restricts the basal activity of σM, and the absence of YhdL leads to runaway expression of the σM regulon and cell death. Here, we report that this lethality can be suppressed by gain-of-function mutations in spoIIIJ, which encodes the major YidC membrane protein insertase in B. subtilis. B. subtilis PY79 SpoIIIJ contains a single amino acid substitution in the substrate-binding channel (Q140K), and this allele suppresses the lethality of high SigM. Analysis of a library of YidC variants reveals that increased charge (+2 or +3) in the substrate-binding channel can compensate for high expression of the σM regulon. Derepression of the σM regulon induces secretion stress, oxidative stress and DNA damage responses, all of which can be alleviated by the YidCQ140K substitution. We further show that the fitness defect caused by high σM activity is exacerbated in the absence of SecDF protein translocase or σM-dependent induction of the Spx oxidative stress regulon. Conversely, cell growth is improved by mutation of specific σM-dependent promoters controlling operons encoding integral membrane proteins. Collectively, these results reveal how the σM regulon has evolved to up-regulate membrane-localized complexes involved in cell wall synthesis, and to simultaneously counter the resulting stresses imposed by regulon induction.Author SummaryBacteria frequently produce antibiotics that inhibit the growth of competitors, and many naturally occurring antibiotics target cell wall synthesis. In Bacillus subtilis, the alternative σ factor σM is induced by cell wall antibiotics, and upregulates genes for peptidoglycan and cell envelope synthesis. However, dysregulation of the σM regulon, resulting from loss of the YhdL anti-σM protein, is lethal. We here identify charge variants of the SpoIIIJ(YidC) membrane protein insertase that suppress the lethal effects of high σM activity. Further analyses reveal that induction of the σM regulon leads to high level expression of membrane proteins that trigger envelope stress, and this stress is countered by specific genes in the σM regulon.

scholarly journals Bacillus subtilis σVConfers Lysozyme Resistance by Activation of Two Cell Wall Modification Pathways, Peptidoglycan O-Acetylation and d-Alanylation of Teichoic Acids

2011 ◽  
Vol 193 (22) ◽  
pp. 6223-6232 ◽  
Author(s):  
Veronica Guariglia-Oropeza ◽  
John D. Helmann
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Double Mutant ◽  
Cell Envelope ◽  
Intrinsic Resistance ◽  
Triple Mutant ◽  
Cell Wall Modification ◽  
Content Type ◽  
Teichoic Acids ◽  
Σ Factor

The seven extracytoplasmic function (ECF) sigma (σ) factors ofBacillus subtilisare broadly implicated in resistance to antibiotics and other cell envelope stressors mediated, in part, by regulation of cell envelope synthesis and modification enzymes. We here define the regulon of σVas including at least 20 operons, many of which are also regulated by σM, σX, or σW. The σVregulon is strongly and specifically induced by lysozyme, and this induction is key to the intrinsic resistance ofB. subtilisto lysozyme. Strains with null mutations in eithersigVor all seven ECF σ factor genes (Δ7ECF) have essentially equal increases in sensitivity to lysozyme. Induction of σVin the Δ7ECF background restores lysozyme resistance, whereas induction of σM, σX, or σWdoes not. Lysozyme resistance results from the ability of σVto activate the transcription of two operons: the autoregulatedsigV-rsiV-oatA-yrhKoperon anddltABCDE. Genetic analyses reveal thatoatAanddltare largely redundant with respect to lysozyme sensitivity: single mutants are not affected in lysozyme sensitivity, whereas anoatA dltAdouble mutant is as sensitive as asigVnull strain. Moreover, thesigV oatA dltAtriple mutant is no more sensitive than theoatA dltAdouble mutant, indicating that there are no other σV-dependent genes necessary for lysozyme resistance. Thus, we suggest that σVconfers lysozyme resistance by the activation of two cell wall modification pathways: O-acetylation of peptidoglycan catalyzed by OatA andd-alanylation of teichoic acids by DltABCDE.

Mutations in transmembrane proteins: diseases, evolutionary insights, prediction and comparison with globular proteins

2020 ◽  
Author(s):  
Jan Zaucha ◽  
Michael Heinzinger ◽  
A Kulandaisamy ◽  
Evans Kataka ◽  
Óscar Llorian Salvádor ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Lipid Bilayers ◽  
Protein Structures ◽  
Experimental Studies ◽  
Single Amino Acid ◽  
Evolutionary Information ◽  
Missense Variants ◽  
Current State ◽  
Aqueous Environments

Abstract Membrane proteins are unique in that they interact with lipid bilayers, making them indispensable for transporting molecules and relaying signals between and across cells. Due to the significance of the protein’s functions, mutations often have profound effects on the fitness of the host. This is apparent both from experimental studies, which implicated numerous missense variants in diseases, as well as from evolutionary signals that allow elucidating the physicochemical constraints that intermembrane and aqueous environments bring. In this review, we report on the current state of knowledge acquired on missense variants (referred to as to single amino acid variants) affecting membrane proteins as well as the insights that can be extrapolated from data already available. This includes an overview of the annotations for membrane protein variants that have been collated within databases dedicated to the topic, bioinformatics approaches that leverage evolutionary information in order to shed light on previously uncharacterized membrane protein structures or interaction interfaces, tools for predicting the effects of mutations tailored specifically towards the characteristics of membrane proteins as well as two clinically relevant case studies explaining the implications of mutated membrane proteins in cancer and cardiomyopathy.

scholarly journals Bacteriophage SP01 Gene Product 56 Inhibits Bacillus subtilis Cell Division by Interacting with FtsL and Disrupting Pbp2B and FtsW Recruitment

2020 ◽  
Vol 203 (2) ◽  
pp. e00463-20
Author(s):  
Amit Bhambhani ◽  
Isabella Iadicicco ◽  
Jules Lee ◽  
Syed Ahmed ◽  
Max Belfatto ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Cell Division ◽  
Gene Product ◽  
Fluorescent Protein ◽  
Lytic Bacteriophage ◽  
Cell Wall Synthesis ◽  
Content Type ◽  
Ftsz Ring ◽  
Green Fluorescent

ABSTRACTPrevious work identified gene product 56 (gp56), encoded by the lytic bacteriophage SP01, as being responsible for inhibition of Bacillus subtilis cell division during its infection. Assembly of the essential tubulin-like protein FtsZ into a ring-shaped structure at the nascent site of cytokinesis determines the timing and position of division in most bacteria. This FtsZ ring serves as a scaffold for recruitment of other proteins into a mature division-competent structure permitting membrane constriction and septal cell wall synthesis. Here, we show that expression of the predicted 9.3-kDa gp56 of SP01 inhibits later stages of B. subtilis cell division without altering FtsZ ring assembly. Green fluorescent protein-tagged gp56 localizes to the membrane at the site of division. While its localization does not interfere with recruitment of early division proteins, gp56 interferes with the recruitment of late division proteins, including Pbp2b and FtsW. Imaging of cells with specific division components deleted or depleted and two-hybrid analyses suggest that gp56 localization and activity depend on its interaction with FtsL. Together, these data support a model in which gp56 interacts with a central part of the division machinery to disrupt late recruitment of the division proteins involved in septal cell wall synthesis.IMPORTANCE Studies over the past decades have identified bacteriophage-encoded factors that interfere with host cell shape or cytokinesis during viral infection. The phage factors causing cell filamentation that have been investigated to date all act by targeting FtsZ, the conserved prokaryotic tubulin homolog that composes the cytokinetic ring in most bacteria and some groups of archaea. However, the mechanisms of several phage factors that inhibit cytokinesis, including gp56 of bacteriophage SP01 of Bacillus subtilis, remain unexplored. Here, we show that, unlike other published examples of phage inhibition of cytokinesis, gp56 blocks B. subtilis cell division without targeting FtsZ. Rather, it utilizes the assembled FtsZ cytokinetic ring to localize to the division machinery and to block recruitment of proteins needed for septal cell wall synthesis.

scholarly journals Tail-Anchored Inner Membrane Protein ElaB Increases Resistance to Stress While Reducing Persistence in Escherichia coli

2017 ◽  
Vol 199 (9) ◽  
Author(s):  
Yunxue Guo ◽  
Xiaoxiao Liu ◽  
Baiyuan Li ◽  
Jianyun Yao ◽  
Thomas K. Wood ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Stationary Phase ◽  
Transmembrane Domain ◽  
Inner Membrane ◽  
Content Type ◽  
E Coli ◽  
Inner Membrane Protein

ABSTRACT Host-associated bacteria, such as Escherichia coli, often encounter various host-related stresses, such as nutritional deprivation, oxidative stress, and temperature shifts. There is growing interest in searching for small endogenous proteins that mediate stress responses. Here, we characterized the small C-tail-anchored inner membrane protein ElaB in E. coli. ElaB belongs to a class of tail-anchored inner membrane proteins with a C-terminal transmembrane domain but lacking an N-terminal signal sequence for membrane targeting. Proteins from this family have been shown to play vital roles, such as in membrane trafficking and apoptosis, in eukaryotes; however, their role in prokaryotes is largely unexplored. Here, we found that the transcription of elaB is induced in the stationary phase in E. coli and stationary-phase sigma factor RpoS regulates elaB transcription by binding to the promoter of elaB. Moreover, ElaB protects cells against oxidative stress and heat shock stress. However, unlike membrane peptide toxins TisB and GhoT, ElaB does not lead to cell death, and the deletion of elaB greatly increases persister cell formation. Therefore, we demonstrate that disruption of C-tail-anchored inner membrane proteins can reduce stress resistance; it can also lead to deleterious effects, such as increased persistence, in E. coli. IMPORTANCE Escherichia coli synthesizes dozens of poorly understood small membrane proteins containing a predicted transmembrane domain. In this study, we characterized the function of the C-tail-anchored inner membrane protein ElaB in E. coli. ElaB increases resistance to oxidative stress and heat stress, while inactivation of ElaB leads to high persister cell formation. We also demonstrated that the transcription of elaB is under the direct regulation of stationary-phase sigma factor RpoS. Thus, our study reveals that small inner membrane proteins may have important cellular roles during the stress response.

scholarly journals Exogenous proanthocyanidins improve tolerance of Cu-toxicity by amelioration of oxidative damage and re-programming of gene expression in Medicago sativa

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0259100
Author(s):  
Siyi Zhao ◽  
Yanqiao Zhu ◽  
Wenwen Liu ◽  
Xiaoshan Wang ◽  
Han Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Wall ◽  
Ascorbic Acid ◽  
Plant Growth ◽  
Medicago Sativa ◽  
Agricultural Practices ◽  
Cell Wall Synthesis ◽  
Genes Encoding ◽  
Stress Damage ◽  
The Impact

Excess copper (Cu) in soil due to industrial and agricultural practices can result in reduced plant growth. Excess Cu resulted in severely retarded root growth with severe discoloration of Alfalfa (Medicago sativa) and Medicago truncatula. Growth in the presence of hydrogen peroxide resulted in similar symptoms that could be partially recovered by the addition of the reductant ascorbic acid revealing damage was likely due to oxidative stress. The addition of proanthocyanidins (PAs) in the presence of Cu prevented much of the damage, including plant growth and restoration of lignin synthesis which was inhibited in the presence of excess Cu. Transcriptome analyses of the impact of excess Cu and the amelioration after PAs treatment revealed that changes were enriched in functions associated with the cell wall and extracellular processes, indicating that inhibition of cell wall synthesis was likely the reason for retarded growth. Excess Cu appeared to induce a strong defense response, along with alterations in the expression of a number of genes encoding transcription factors, notably related to ethylene signaling. The addition of PAs greatly reduced this response, and also induced novel genes that likely help ameliorate the effects of excess Cu. These included induction of genes involved in the last step of ascorbic acid biosynthesis and of enzymes involved in cell wall synthesis. Combined, these results show that excess Cu causes severe oxidative stress damage and inhibition of cell wall synthesis, which can be relieved by the addition of PAs.

scholarly journals Stress-Responsive Systems Set Specific Limits to the Overproduction of Membrane Proteins in Bacillus subtilis

2009 ◽  
Vol 75 (23) ◽  
pp. 7356-7364 ◽  
Author(s):  
Jessica C. Zweers ◽  
Thomas Wiegert ◽  
Jan Maarten van Dijl
Keyword(s):  
Bacillus Subtilis ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Drug Targets ◽  
Protein Production ◽  
Cell Envelope ◽  
Regulatory System ◽  
Interesting Candidate ◽  
High Level ◽  
And Function

ABSTRACT Essential membrane proteins are generally recognized as relevant potential drug targets due to their exposed localization in the cell envelope. Unfortunately, high-level production of membrane proteins for functional and structural analyses is often problematic. This is mainly due to their high overall hydrophobicity. To develop new concepts for membrane protein overproduction, we investigated whether the biogenesis of overproduced membrane proteins is affected by stress response-related proteolytic systems in the membrane. For this purpose, the well-established expression host Bacillus subtilis was used to overproduce eight essential membrane proteins from B. subtilis and Staphylococcus aureus. The results show that the σW regulon (responding to cell envelope perturbations) and the CssRS two-component regulatory system (responding to unfolded exported proteins) set critical limits to membrane protein production in large quantities. The identified sigW or cssRS mutant B. subtilis strains with significantly improved capacity for membrane protein production are interesting candidate expression hosts for fundamental research and biotechnological applications. Importantly, our results pinpoint the interdependent expression and function of membrane-associated proteases as key parameters in bacterial membrane protein production.

scholarly journals DivIVA Is Required for Polar Growth in the MreB-Lacking Rod-Shaped Actinomycete Corynebacterium glutamicum

2008 ◽  
Vol 190 (9) ◽  
pp. 3283-3292 ◽  
Author(s):  
Michal Letek ◽  
Efrén Ordóñez ◽  
José Vaquera ◽  
William Margolin ◽  
Klas Flärdh ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Cell Division ◽  
Streptococcus Pneumoniae ◽  
Corynebacterium Glutamicum ◽  
Chromosome Segregation ◽  
Polar Growth ◽  
Cell Wall Synthesis ◽  
Peptidoglycan Synthesis ◽  
Polarized Cell Growth

ABSTRACT The actinomycete Corynebacterium glutamicum grows as rod-shaped cells by zonal peptidoglycan synthesis at the cell poles. In this bacterium, experimental depletion of the polar DivIVA protein (DivIVACg) resulted in the inhibition of polar growth; consequently, these cells exhibited a coccoid morphology. This result demonstrated that DivIVA is required for cell elongation and the acquisition of a rod shape. DivIVA from Streptomyces or Mycobacterium localized to the cell poles of DivIVACg-depleted C. glutamicum and restored polar peptidoglycan synthesis, in contrast to DivIVA proteins from Bacillus subtilis or Streptococcus pneumoniae, which localized at the septum of C. glutamicum. This confirmed that DivIVAs from actinomycetes are involved in polarized cell growth. DivIVACg localized at the septum after cell wall synthesis had started and the nucleoids had already segregated, suggesting that in C. glutamicum DivIVA is not involved in cell division or chromosome segregation.

scholarly journals Hydrophilic microenvironment required for the channel-independent insertase function of YidC protein

2015 ◽  
Vol 112 (16) ◽  
pp. 5063-5068 ◽  
Author(s):  
Naomi Shimokawa-Chiba ◽  
Kaoru Kumazaki ◽  
Tomoya Tsukazaki ◽  
Osamu Nureki ◽  
Koreaki Ito ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Bacillus Subtilis ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Protein Translocation ◽  
Cavity Surface ◽  
Energetic Costs ◽  
Protein Insertion ◽  
Membrane Protein Insertion ◽  
Alternative Sites

The recently solved crystal structure of YidC protein suggests that it mediates membrane protein insertion by means of an intramembrane cavity rather than a transmembrane (TM) pore. This concept of protein translocation prompted us to characterize the native, membrane-integrated state of YidC with respect to the hydropathic nature of its TM region. Here, we show that the cavity-forming region of the stage III sporulation protein J (SpoIIIJ), a YidC homolog, is indeed open to the aqueous milieu of the Bacillus subtilis cells and that the overall hydrophilicity of the cavity, along with the presence of an Arg residue on several alternative sites of the cavity surface, is functionally important. We propose that YidC functions as a proteinaceous amphiphile that interacts with newly synthesized membrane proteins and reduces energetic costs of their membrane traversal.

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