Active invasion of bacteria into living fungal cells

The rice seedling blight fungus Rhizopus microsporus and its endosymbiont Burkholderia rhizoxinica form an unusual, highly specific alliance to produce the highly potent antimitotic phytotoxin rhizoxin. Yet, it has remained a riddle how bacteria invade the fungal cells. Genome mining for potential symbiosis factors and functional analyses revealed that a type 2 secretion system (T2SS) of the bacterial endosymbiont is required for the formation of the endosymbiosis. Comparative proteome analyses show that the T2SS releases chitinolytic enzymes (chitinase, chitosanase) and chitin-binding proteins. The genes responsible for chitinolytic proteins and T2SS components are highly expressed during infection. Through targeted gene knock-outs, sporulation assays and microscopic investigations we found that chitinase is essential for bacteria to enter hyphae. Unprecedented snapshots of the traceless bacterial intrusion were obtained using cryo-electron microscopy. Beyond unveiling the pivotal role of chitinolytic enzymes in the active invasion of a fungus by bacteria, these findings grant unprecedented insight into the fungal cell wall penetration and symbiosis formation.

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Cryo-EM structures of the DCPIB-inhibited volume-regulated anion channel LRRC8A in lipid nanodiscs

10.1101/442459 ◽

2018 ◽

Cited By ~ 2

Author(s):

David M. Kern ◽

SeCheol Oh ◽

Richard K. Hite ◽

Stephen G. Brohawn

Keyword(s):

Lipid Bilayers ◽

Critical Role ◽

Anion Channel ◽

Lipid Binding ◽

Channel Structure ◽

Anion Channels ◽

Cryo Electron Microscopy ◽

Lipid Nanodiscs ◽

Insight Into

AbstractHypoosmotic conditions activate volume-regulated anion channels in vertebrate cells. These channels are formed by leucine-rich repeat-containing protein 8 (LRRC8) family members and contain LRRC8A in homo- or hetero-hexameric assemblies. Here we present single-particle cryo-electron microscopy structures of LRRC8A in complex with the inhibitor DCPIB reconstituted in lipid nanodiscs. DCPIB plugs the channel like a cork in a bottle - binding in the extracellular selectivity filter and sterically occluding ion conduction. Constricted and expanded structures reveal coupled dilation of cytoplasmic LRRs and the channel pore, suggesting a mechanism for channel gating by internal stimuli. Conformational and symmetry differences between LRRC8A structures determined in detergent micelles and lipid bilayers related to reorganization of intersubunit lipid binding sites demonstrate a critical role for the membrane in determining channel structure. These results provide insight into LRRC8 gating and inhibition and the role of lipids in the structure of an ionic-strength sensing ion channel.

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Cryo-EM structure of 90S small ribosomal subunit precursors in transition states

Science ◽

10.1126/science.aba9690 ◽

2020 ◽

Vol 369 (6510) ◽

pp. 1477-1481 ◽

Cited By ~ 3

Author(s):

Yifei Du ◽

Weidong An ◽

Xing Zhu ◽

Qi Sun ◽

Jia Qi ◽

...

Keyword(s):

Structural Changes ◽

Critical Role ◽

Ribosomal Subunit ◽

Rna Degradation ◽

Ribosomal Subunits ◽

Cryo Electron Microscopy ◽

Nuclear Exosome ◽

Assembly Intermediate ◽

Insight Into

The 90S preribosome is a large, early assembly intermediate of small ribosomal subunits that undergoes structural changes to give a pre-40S ribosome. Here, we gained insight into this transition by determining cryo–electron microscopy structures of Saccharomyces cerevisiae intermediates in the path from the 90S to the pre-40S. The full transition is blocked by deletion of RNA helicase Dhr1. A series of structural snapshots revealed that the excised 5′ external transcribed spacer (5′ ETS) is degraded within 90S, driving stepwise disassembly of assembly factors and ribosome maturation. The nuclear exosome, an RNA degradation machine, docks on the 90S through helicase Mtr4 and is primed to digest the 3′ end of the 5′ ETS. The structures resolved between 3.2- and 8.6-angstrom resolution reveal key intermediates and the critical role of 5′ ETS degradation in 90S progression.

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Cryo-EM structure of native human thyroglobulin

10.1101/2021.06.06.447243 ◽

2021 ◽

Author(s):

Ricardo Adaixo ◽

Eva M. Steiner ◽

Ricardo D. Righetto ◽

Alexander Schmidt ◽

Henning Stahlberg ◽

...

Keyword(s):

Secretory Pathway ◽

3D Structure ◽

Vital Role ◽

Hormone Synthesis ◽

Cryo Electron Microscopy ◽

Glycosylation Sites ◽

Regulation Of Metabolism ◽

Fundamental Understanding ◽

Insight Into

The thyroglobulin (Tg) protein is essential to thyroid hormone synthesis, playing a vital role in the regulation of metabolism, development and growth. Its structure is conserved among vertebrates. Tg is delivered through the secretory pathway of the thyroid follicular unit to the central colloid depository, where it is iodinated at specific tyrosine sites to form mono- or diiodotyrosine, which combine to produce triiodothyronine (T3) and thyroxine (T4), respectively. Synthesis of these hormones depends on the precise 3D structure of Tg, which has remained unknown despite decades of research. Here, we present the cryo-electron microscopy structure of human thyroglobulin (hTg) to a global resolution of 3.2 Å. The structure provides detailed information on the location of the hTg hormonogenic sites and reveals the position as well as the role of many of its glycosylation sites. Our results offer structural insight into thyroid hormonogenesis and provide a fundamental understanding of clinically relevant hTg mutations, which can improve treatment of thyroid diseases.

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Cryo-EM structure of native human thyroglobulin

10.21203/rs.3.rs-599631/v1 ◽

2021 ◽

Author(s):

Ricardo Adaixo ◽

Eva Steiner ◽

Ricardo Righetto ◽

Alexander Schmidt ◽

Henning Stahlberg ◽

...

Keyword(s):

Secretory Pathway ◽

3D Structure ◽

Vital Role ◽

Hormone Synthesis ◽

Cryo Electron Microscopy ◽

Glycosylation Sites ◽

Regulation Of Metabolism ◽

Fundamental Understanding ◽

Insight Into

Abstract The thyroglobulin (Tg) protein is essential to thyroid hormone synthesis, playing a vital role in the regulation of metabolism, development and growth. Its structure is conserved among vertebrates. Tg is delivered through the secretory pathway of the thyroid follicular unit to the central colloid depository, where it is iodinated at specific tyrosine sites to form mono- or diiodotyrosine, which combine to produce triiodothyronine (T3) and thyroxine (T4), respectively. Synthesis of these hormones depends on the precise 3D structure of Tg, which has remained unknown despite decades of research. Here, we present the cryo-electron microscopy structure of human thyroglobulin (hTg) to a global resolution of 3.2 Å. The structure provides detailed information on the location of the hTg hormonogenic sites and reveals the position as well as the role of many of its glycosylation sites. Our results offer structural insight into thyroid hormonogenesis and provide a fundamental understanding of clinically relevant hTg mutations, which can improve treatment of thyroid diseases.

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A key role for IL-13 signaling via the type 2 IL-4 receptor in experimental atopic dermatitis

Science Immunology ◽

10.1126/sciimmunol.aaw2938 ◽

2020 ◽

Vol 5 (44) ◽

pp. eaaw2938 ◽

Cited By ~ 5

Author(s):

Almog Bitton ◽

Shmuel Avlas ◽

Hadar Reichman ◽

Michal Itan ◽

Danielle Karo-Atar ◽

...

Keyword(s):

Atopic Dermatitis ◽

Allergic Diseases ◽

Proof Of Concept ◽

Potential Therapeutic Target ◽

Tnf Α ◽

Allergic Skin ◽

Insight Into

IL-13 and IL-4 are potent mediators of type 2–associated inflammation such as those found in atopic dermatitis (AD). IL-4 shares overlapping biological functions with IL-13, a finding that is mainly explained by their ability to signal via the type 2 IL-4 receptor (R), which is composed of IL-4Rα in association with IL-13Rα1. Nonetheless, the role of the type 2 IL-4R in AD remains to be clearly defined. Induction of two distinct models of experimental AD in Il13ra1−/− mice, which lack the type 2 IL-4R, revealed that dermatitis, including ear and epidermal thickening, was dependent on type 2 IL-4R signaling. Expression of TNF-α was dependent on the type 2 IL-4R, whereas induction of IL-4, IgE, CCL24, and skin eosinophilia was dependent on the type 1 IL-4R. Neutralization of IL-4, IL-13, and TNF-α as well as studies in bone marrow–chimeric mice revealed that dermatitis, TNF-α, CXCL1, and CCL11 expression were exclusively mediated by IL-13 signaling via the type 2 IL-4R expressed by nonhematopoietic cells. Conversely, induction of IL-4, CCL24, and eosinophilia was dependent on IL-4 signaling via the type 1 IL-4R expressed by hematopoietic cells. Last, we pharmacologically targeted IL-13Rα1 and established a proof of concept for therapeutic targeting of this pathway in AD. Our data provide mechanistic insight into the differential roles of IL-4, IL-13, and their receptor components in allergic skin and highlight type 2 IL-4R as a potential therapeutic target in AD and other allergic diseases such as asthma and eosinophilic esophagitis.

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Renalase gene Glu37Asp polymorphism affects susceptibility to diabetic retinopathy in type 2 diabetes mellitus

Acta Diabetologica ◽

10.1007/s00592-021-01740-8 ◽

2021 ◽

Author(s):

Monika Buraczynska ◽

Karolina Gwiazda-Tyndel ◽

Bartłomiej Drop ◽

Wojciech Zaluska

Keyword(s):

Type 2 Diabetes ◽

Diabetic Retinopathy ◽

Case Control Study ◽

Microvascular Complications ◽

Monoamine Oxidase Activity ◽

Allele Distribution ◽

Insight Into ◽

Control Study

Abstract Aims Renalase (RNLS) is an enzyme with monoamine oxidase activity that metabolizes circulating catecholamines. The RNLS gene Asp37Glu missense polymorphism (rs2296545) has been associated with hypertension, cardiac hypertrophy and dysfunction, and stroke. The purpose of our study was to investigate the potential involvement of this polymorphism in the microvascular complications of type 2 diabetes (T2DM). Methods In this case–control study, the polymorphism was genotyped in 860 patients with T2DM and 400 healthy controls. The genotype and allele distribution was compared in subgroups of patients: with diabetic nephropathy (DN+) (n = 405) versus DN− (independently of the presence of DR) and, similarly, patients with diabetic retinopathy (DR+) (n = 328) versus DR− (independently of the presence of DN). Results No significant association was detected between analyzed polymorphism and DN. In contrast, the retinopathy subgroup showed a significantly higher frequency of G allele (OR 1.4, 95% CI 1.16–1.72, p = 0.0005) and GG genotype (OR 1.86, 95% CI 1.26–2.75, p = 0.001) than DR− patients. The effect of RNLS Glu37Asp polymorphism on DR remained significant after adjustments for age, gender, BMI, and duration of T2DM (p = 0.005). Conclusions This is the first study to investigate RNLS gene polymorphism in microvascular complications of T2DM. The results suggest that RNLS rs2296545 SNP might be considered a risk factor for diabetic retinopathy in T2DM patients. This can provide new insight into the role of renalase gene in the pathophysiology of microvascular complications of diabetes.

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Discovering the Role of Emotional and Rational Appeals and Hidden Heterogeneity of Consumers in Advertising Copies for Sustainable Marketing

Sustainability ◽

10.3390/su12125189 ◽

2020 ◽

Vol 12 (12) ◽

pp. 5189 ◽

Cited By ~ 2

Author(s):

Cheong Kim ◽

Hyeon Gyu Jeon ◽

Kun Chang Lee

Keyword(s):

Unobserved Heterogeneity ◽

Practical Implication ◽

Marketing Strategies ◽

Consumer Group ◽

Sustainable Marketing ◽

Type 3 ◽

Insight Into

Advertising copies have been considered as a fundamental strategy for firms to continue sustainable marketing strategies. In order to provide the advancement of previous research and practical implication to marketers in the field for sustainable marketing strategy, this research tried to reveal the role of emotional and rational appeals as well as hidden heterogeneity of consumers in the appeal–value–trust–satisfaction–WOM framework. By applying the PLS-SEM and PLS-POS approach to 230 valid questionnaire samples, we could discover the role of appeals in the framework as well as three types of unobserved heterogeneity among the respondents. Both emotional and rational appeals had significant influences on the value–satisfaction–trust–WOM context. In addition, for hidden consumer traits in advertising copies, we revealed three types of consumer groups: Type 1, the consumer group with a rational orientation (n = 68); Type 2, the group with an emotional orientation (n = 74) and Type 3, the group with a utilitarian orientation. This research provided contributions by offering some insight into ways to establish sustainable marketing strategies in advertisements and to address unobserved heterogeneity consumers in advertising copy appeals.

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Insight into Polyphenol and Gut Microbiota Crosstalk: Are Their Metabolites the Key to Understand Protective Effects against Metabolic Disorders?

Antioxidants ◽

10.3390/antiox9100982 ◽

2020 ◽

Vol 9 (10) ◽

pp. 982 ◽

Cited By ~ 1

Author(s):

Mireille Koudoufio ◽

Yves Desjardins ◽

Francis Feldman ◽

Schohraya Spahis ◽

Edgard Delvin ◽

...

Keyword(s):

Gut Microbiota ◽

Human Organism ◽

Protective Effects ◽

Dietary Polyphenols ◽

Cardiometabolic Disorders ◽

Progression Of Disease ◽

Anti Oxidant ◽

Insight Into

Lifestyle factors, especially diet and nutrition, are currently regarded as essential avenues to decrease modern-day cardiometabolic disorders (CMD), including obesity, metabolic syndrome, type 2 diabetes, and atherosclerosis. Many groups around the world attribute these trends, at least partially, to bioactive plant polyphenols given their anti-oxidant and anti-inflammatory actions. In fact, polyphenols can prevent or reverse the progression of disease processes through many distinct mechanisms. In particular, the crosstalk between polyphenols and gut microbiota, recently unveiled thanks to DNA-based tools and next generation sequencing, unravelled the central regulatory role of dietary polyphenols and their intestinal micro-ecology metabolites on the host energy metabolism and related illnesses. The objectives of this review are to: (1) provide an understanding of classification, structure, and bioavailability of dietary polyphenols; (2) underline their metabolism by gut microbiota; (3) highlight their prebiotic effects on microflora; (4) discuss the multifaceted roles of their metabolites in CMD while shedding light on the mechanisms of action; and (5) underscore their ability to initiate host epigenetic regulation. In sum, the review clearly documents whether dietary polyphenols and micro-ecology favorably interact to promote multiple physiological functions on human organism.

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Use of stereoisomers of zacopride to analyze actions of 5-hydroxytryptamine on enteric neurons

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1991.260.1.g80 ◽

1991 ◽

Vol 260 (1) ◽

pp. G80-G90 ◽

Cited By ~ 1

Author(s):

P. R. Wade ◽

G. M. Mawe ◽

T. A. Branchek ◽

M. D. Gershon

Keyword(s):

Receptor Antagonist ◽

Enteric Neurons ◽

Myenteric Neurons ◽

Substituted Benzamide ◽

A Site ◽

Ics 205 930 ◽

Fold Excess ◽

Insight Into

Two subtypes of excitatory 5-hydroxytryptamine (5-HT) receptor, 5-HT1P and 5-HT3, are found on type 2-AH neurons of the guinea pig myenteric plexus. The 5-HT1P receptor mediates a slow and the 5-HT3 receptor a fast depolarization of these cells, however, the role of these receptors in the physiology of the gut is unknown. Renzapride (BRL 24924), a substituted benzamide, has previously been found to antagonize responses of myenteric neurons mediated by both 5-HT1P and 5-HT3 receptors. The effects on myenteric type 2-AH neurons of a structurally similar benzamide, zacopride, which unlike renzapride has S and R stereoisomers, were investigated to gain further insight into 5-HT receptor function. In contrast to renzapride, S-, but not R-zacopride, was found to mimic the 5-HT1P receptor-mediated slow response to 5-HT. Desensitization of 5-HT1P receptors with 5-HT inhibited slow depolarizing responses to S-zacopride, and desensitization with S-zacopride antagonized slow responses to 5-HT. Responses to S-zacopride were also inhibited by renzapride and the 5-HT1P receptor antagonist N-acetyl-5-hydroxytryptophyl-5-hydroxytryptophan amide (5-HTP-DP). S-zacopride, like renzapride and 5-HT, presynaptically inhibited nicotinic fast excitatory postsynaptic potentials, an effect that can be mediated by 5-HT1P or 5-HT1A receptors. Both S and R stereoisomers of zacopride antagonized 5-HT3 receptor-mediated fast responses to 5-HT. Unlike 5-HTP-DP, neither zacopride or its stereoisomers nor renzapride inhibited the binding of 5-[3H]HT to 5-HT1P receptors. [3H]zacopride (5-10 nM) was found to bind to a site in the gut from which it could be displaced by a 1,000-fold excess of renzapride and S-zacopride (but not R-zacopride) greater than 5-HTP-DP much greater than the 5-HT3 receptor antagonist ICS 205-930. These observations suggest that, in addition to 5-HT3 receptors, there is a benzamide binding site on myenteric neurons that interacts with, but is distinct from, the 5-HT recognition site of 5-HT1P receptors. Benzamides may affect coupling of the 5-HT1P receptor to its effector.

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Insight into the Role of Angiopoietins in Ageing-Associated Diseases

Cells ◽

10.3390/cells9122636 ◽

2020 ◽

Vol 9 (12) ◽

pp. 2636

Author(s):

Shin-ichiro Hayashi ◽

Hiromi Rakugi ◽

Ryuichi Morishita

Keyword(s):

Signaling Pathway ◽

Clinical Applications ◽

Vascular Endothelial ◽

Major Pathway ◽

Associated Diseases ◽

Antiangiogenic Therapies ◽

Endothelial Growth Factor ◽

Insight Into

Angiopoietin (Ang) and its receptor, TIE signaling, contribute to the development and maturation of embryonic vasculature as well as vascular remodeling and permeability in adult tissues. Targeting both this signaling pathway and the major pathway with vascular endothelial growth factor (VEGF) is expected to permit clinical applications, especially in antiangiogenic therapies against tumors. Several drugs targeting the Ang-TIE signaling pathway in cancer patients are under clinical development. Similar to how cancer increases with age, unsuitable angiogenesis or endothelial dysfunction is often seen in other ageing-associated diseases (AADs) such as atherosclerosis, Alzheimer’s disease, type 2 diabetes, chronic kidney disease and cardiovascular diseases. Thus, the Ang-TIE pathway is a possible molecular target for AAD therapy. In this review, we focus on the potential role of the Ang-TIE signaling pathway in AADs, especially non-cancer-related AADs. We also suggest translational insights and future clinical applications of this pathway in those AADs.

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