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Otsuka M, Huang J, Tanaka T, Sakata I. Identification of glucagon like peptide-1 (GLP-1) in mice stomach. Biochem Biophys Res Commun 2024; 704:149708. [PMID: 38417346 DOI: 10.1016/j.bbrc.2024.149708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 02/18/2024] [Accepted: 02/20/2024] [Indexed: 03/01/2024]
Abstract
Glucagon like peptide-1 (GLP-1) is a peptide hormone encoded by the pre-proglucagon gene that serves multiple physiological functions, including incretin action. While GLP-1 is primarily synthesized in the L cells of the lower intestine, recent findings indicate its presence in the stomachs of both rats and humans. However, the role of gastric GLP-1 in other species remains unclear. In this study, we aimed to identify GLP-1-producing cells and examine the localization of GLP-1 production in the mouse stomach. We found that pre-proglucagon mRNA was higher in the corpus than that in the antrum of the stomach. In addition, GLP-1 immunoreactive cells were found in the gastric mucosa, and their cell number was higher in the corpus than that in the antrum. Double immunofluorescence showed that some GLP-1 immunoreactive cells displayed somatostatin immunoreactivity, whereas did not co-localize with ghrelin and gastrin. Moreover, transmembrane G protein-coupled Receptor 5 (TGR5) agonist decreased pre-proglucagon mRNA expression in SG-1 cells in a concentration-dependent manner, and in vivo experiments showed a decrease in its mRNA levels in the gastric corpus but not in the antrum. This study marks the first report of GLP-1 production in the mouse stomach. Our findings suggest that gastric pre-proglucagon mRNA expression is regulated by a distinct mechanism compared to the L cells of the lower intestine.
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Affiliation(s)
- Manami Otsuka
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Jin Huang
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Toru Tanaka
- Faculty of Pharmacy and Pharmaceutical Sciences, Department of Pharmaceutical Sciences, Josai University, Saitama, 1-1 Keiyaki dai, Sakado, Saitama, 350-0295, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakura-ku, Saitama, 338-8570, Japan; Area of Research Evolutionary Molecular Design, Strategic Research Center, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan.
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2
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Martin-Martin I, Valenzuela Leon PC, Amo L, Shrivastava G, Iniguez E, Aryan A, Brooks S, Kojin BB, Williams AE, Bolland S, Ackerman H, Adelman ZN, Calvo E. Aedes aegypti sialokinin facilitates mosquito blood feeding and modulates host immunity and vascular biology. Cell Rep 2022; 39:110648. [PMID: 35417706 PMCID: PMC9082008 DOI: 10.1016/j.celrep.2022.110648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/01/2022] [Accepted: 03/17/2022] [Indexed: 11/28/2022] Open
Abstract
Saliva from mosquitoes contains vasodilators that antagonize vasoconstrictors produced at the bite site. Sialokinin is a vasodilator present in the saliva of Aedes aegypti. Here, we investigate its function and describe its mechanism of action during blood feeding. Sialokinin induces nitric oxide release similar to substance P. Sialokinin-KO mosquitoes produce lower blood perfusion than parental mosquitoes at the bite site during probing and have significantly longer probing times, which result in lower blood feeding success. In contrast, there is no difference in feeding between KO and parental mosquitoes when using artificial membrane feeders or mice that are treated with a substance P receptor antagonist, confirming that sialokinin interferes with host hemostasis via NK1R signaling. While sialokinin-KO saliva does not affect virus infection in vitro, it stimulates macrophages and inhibits leukocyte recruitment in vivo. This work highlights the biological functionality of salivary proteins in blood feeding.
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Affiliation(s)
- Ines Martin-Martin
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA.
| | - Paola Carolina Valenzuela Leon
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Laura Amo
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Gaurav Shrivastava
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Eva Iniguez
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Azadeh Aryan
- Department of Entomology and Fralin Life Science Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
| | - Steven Brooks
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Bianca B Kojin
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA
| | - Adeline E Williams
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA; Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins 80523, CO, USA
| | - Silvia Bolland
- Department of Entomology and Fralin Life Science Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
| | - Hans Ackerman
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Zach N Adelman
- Department of Entomology and Fralin Life Science Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA; Department of Entomology, Texas A&M University, College Station, TX 77843, USA
| | - Eric Calvo
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA.
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3
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The Path to Therapeutic Furin Inhibitors: From Yeast Pheromones to SARS-CoV-2. Int J Mol Sci 2022; 23:ijms23073435. [PMID: 35408793 PMCID: PMC8999023 DOI: 10.3390/ijms23073435] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 02/06/2023] Open
Abstract
The spurious acquisition and optimization of a furin cleavage site in the SARS-CoV-2 spike protein is associated with increased viral transmission and disease, and has generated intense interest in the development and application of therapeutic furin inhibitors to thwart the COVID-19 pandemic. This review summarizes the seminal studies that informed current efforts to inhibit furin. These include the convergent efforts of endocrinologists, virologists, and yeast geneticists that, together, culminated in the discovery of furin. We describe the pioneering biochemical studies which led to the first furin inhibitors that were able to block the disease pathways which are broadly critical for pathogen virulence, tumor invasiveness, and atherosclerosis. We then summarize how these studies subsequently informed current strategies leading to the development of small-molecule furin inhibitors as potential therapies to combat SARS-CoV-2 and other diseases that rely on furin for their pathogenicity and progression.
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4
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New Insights in the Control of Fat Homeostasis: The Role of Neurotensin. Int J Mol Sci 2022; 23:ijms23042209. [PMID: 35216326 PMCID: PMC8876516 DOI: 10.3390/ijms23042209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/07/2022] [Accepted: 02/15/2022] [Indexed: 12/10/2022] Open
Abstract
Neurotensin (NT) is a small peptide with pleiotropic functions, exerting its primary actions by controlling food intake and energy balance. The first evidence of an involvement of NT in metabolism came from studies on the central nervous system and brain circuits, where NT acts as a neurotransmitter, producing different effects in relation to the specific region involved. Moreover, newer interesting chapters on peripheral NT and metabolism have emerged since the first studies on the NT-mediated regulation of gut lipid absorption and fat homeostasis. Intriguingly, NT enhances fat absorption from the gut lumen in the presence of food with a high fat content, and this action may explain the strong association between high circulating levels of pro-NT, the NT stable precursor, and the increased incidence of metabolic disorders, cardiovascular diseases, and cancer observed in large population studies. This review aims to provide a synthetic overview of the main regulatory effects of NT on several biological pathways, particularly those involving energy balance, and will focus on new evidence on the role of NT in controlling fat homeostasis, thus influencing the risk of unfavorable cardio–metabolic outcomes and overall mortality in humans.
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5
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Kusunoki H, Tanaka T, Ohshima C, Sakamoto T, Wakamatsu K, Hamaguchi I. The N93D mutation of the human T-cell leukemia virus type 1 envelope glycoprotein found in symptomatic patients enhances neuropilin-1 b1 domain binding. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2021; 1869:140708. [PMID: 34343702 DOI: 10.1016/j.bbapap.2021.140708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/19/2021] [Accepted: 07/23/2021] [Indexed: 10/20/2022]
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) infection of host cells is mainly mediated by interactions with the viral envelope glycoprotein surface unit (SU) and three host receptors: heparan sulfate proteoglycan, neuropilin-1 (Nrp1), and glucose transporter type 1. Residues 90-94 of SU are considered as a Nrp1 binding site, and our previous results show that an SU peptide consisting of residues 85-94 can bind directly to the Nrp1 b1 domain with a binding affinity of 7.4 μM. Therefore, the SU peptide is expected to be a good model to investigate the SU-Nrp1 interaction. Recently, the N93D mutation in the Nrp1 b1 binding region of the SU was identified in symptomatic patients with HTLV-1 infections in the Brazilian Amazon. However, it remains unclear how the SU-N93D mutation affects Nrp1 b1 binding. To elucidate the impact of the substituted Asp93 of SU on Nrp1 b1 binding, we analyzed the interaction between the SU-N93D peptide and Nrp1 b1 using isothermal titration calorimetry and nuclear magnetic resonance. The SU-N93D peptide binds directly to Nrp1 b1 with a binding affinity of 3.5 μM, which is approximately two-fold stronger than wild-type. This stronger binding is likely a result of the interaction between the substituted residue Asp93 of the N93D peptide and the four residues Trp301, Lys347, Glu348, and Thr349 of Nrp1 b1. Our results suggest that the interaction of SU Asp93 with the four residues of Nrp1 b1 renders the high affinity of the N93D mutant for Nrp1 b1 binding during HTLV-1 entry.
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Affiliation(s)
- Hideki Kusunoki
- Department of Safety Research on Blood and Biological Products, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan.
| | - Toshiyuki Tanaka
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Life Science Center, Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Chinatsu Ohshima
- Department of Safety Research on Blood and Biological Products, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan
| | - Taiichi Sakamoto
- Department of Life Science, Faculty of Advanced Engineering, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016, Japan
| | - Kaori Wakamatsu
- Department of Molecular Science, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Isao Hamaguchi
- Department of Safety Research on Blood and Biological Products, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan
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6
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Wen F, Yang J, Guo J, Wang C, Cheng Q, Tang Z, Luo K, Yuan S, Huang S, Li Y. Genetic characterization of an H5N6 avian influenza virus with multiple origins from a chicken in southern China, October 2019. BMC Vet Res 2021; 17:200. [PMID: 34049549 PMCID: PMC8161609 DOI: 10.1186/s12917-021-02903-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 05/17/2021] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Highly pathogenic avian influenza viruses (HPAIVs) of H5 subtype pose a great threat to the poultry industry and human health. In recent years, H5N6 subtype has rapidly replaced H5N1 as the most predominate HPAIV subtype circulating in domestic poultry in China. In this study, we describe the genetic and phylogenetic characteristics of a prevalent H5N6 strain in Guangdong, China. RESULTS Nucleotide sequencing identified a H5N6 subtype HPAIV, designated as A/chicken/Dongguan/1101/2019 (DG/19), with a multibasic cleavage site in the hemagglutinin (HA). Phylogenetic analysis revealed DG/19 was a reassortant of H5N1, H5N2, H5N8, and H6N6 subtypes of avian influenza viruses. A number of mammalian adaptive markers such as D36N in the HA were identified. CONCLUSIONS Our results showed that HPAIV H5N6 strains still emerge in well-managed groups of chicken farms. Considering the increasing prevalence of H5N6 HPAIV, and the fact that H5N6 HPAIVs are well adapted to migratory birds, an enhanced surveillance for the East Asian-Australasian flyway should be undertaken to prevent potential threats to the poultry industry and human health.
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Affiliation(s)
- Feng Wen
- College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China.
| | - Jing Yang
- College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Jinyue Guo
- College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Congying Wang
- College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Qing Cheng
- College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Zheng Tang
- College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Kaijian Luo
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Sheng Yuan
- College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Shujian Huang
- College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Yong Li
- College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, 330045, Jiangxi, China.
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7
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Lafferty RA, O’Harte FPM, Irwin N, Gault VA, Flatt PR. Proglucagon-Derived Peptides as Therapeutics. Front Endocrinol (Lausanne) 2021; 12:689678. [PMID: 34093449 PMCID: PMC8171296 DOI: 10.3389/fendo.2021.689678] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/05/2021] [Indexed: 12/12/2022] Open
Abstract
Initially discovered as an impurity in insulin preparations, our understanding of the hyperglycaemic hormone glucagon has evolved markedly over subsequent decades. With description of the precursor proglucagon, we now appreciate that glucagon was just the first proglucagon-derived peptide (PGDP) to be characterised. Other bioactive members of the PGDP family include glucagon-like peptides -1 and -2 (GLP-1 and GLP-2), oxyntomodulin (OXM), glicentin and glicentin-related pancreatic peptide (GRPP), with these being produced via tissue-specific processing of proglucagon by the prohormone convertase (PC) enzymes, PC1/3 and PC2. PGDP peptides exert unique physiological effects that influence metabolism and energy regulation, which has witnessed several of them exploited in the form of long-acting, enzymatically resistant analogues for treatment of various pathologies. As such, intramuscular glucagon is well established in rescue of hypoglycaemia, while GLP-2 analogues are indicated in the management of short bowel syndrome. Furthermore, since approval of the first GLP-1 mimetic for the management of Type 2 diabetes mellitus (T2DM) in 2005, GLP-1 therapeutics have become a mainstay of T2DM management due to multifaceted and sustainable improvements in glycaemia, appetite control and weight loss. More recently, longer-acting PGDP therapeutics have been developed, while newfound benefits on cardioprotection, bone health, renal and liver function and cognition have been uncovered. In the present article, we discuss the physiology of PGDP peptides and their therapeutic applications, with a focus on successful design of analogues including dual and triple PGDP receptor agonists currently in clinical development.
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Affiliation(s)
| | | | | | - Victor A. Gault
- School of Biomedical Sciences, Ulster University, Coleraine, United Kingdom
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8
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Sharker MR, Nou IS, Kho KH. Molecular characterization and spatiotemporal expression of prohormone convertase 2 in the Pacific abalone, Haliotis discus hannai. PLoS One 2020; 15:e0231353. [PMID: 32271824 PMCID: PMC7144994 DOI: 10.1371/journal.pone.0231353] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 03/20/2020] [Indexed: 11/18/2022] Open
Abstract
Prohormone convertases (PCs) are subtilisin-like proteases responsible for the intracellular processing of prohormones and proneuropeptides in vertebrates and invertebrates. The full-length PC2 cDNA sequence was cloned from pleuropedal ganglion of Haliotis discus hannai, consisted of 2254-bp with an open reading frame of 1989-bp and encoded a protein of 662 amino acid residues. The architecture of Hdh PC2 displayed key features of PCs, including a signal peptide, a pro-segment domain with sites for autocatalytic activation, a catalytic domain, and a pro-protein domain (P-domain). It shares the highest homology of its amino acid sequence with the PC2 from H. asinina and to lesser extent with that of Homo sapiens and Rana catesbeiana PC2. Sequence alignment analysis indicated that Hdh PC2 was highly conserved in the catalytic domain, including a catalytic triad of serine proteinases of the subtilisin family at positions Asp-195, His-236, and Ser-412. The cloned sequence contained a canonical integrin binding sequence, and four cysteine residues involved in the formation of an intramolecular disulfide link. Phylogenetic analysis revealed that the Hdh PC2 is robustly clustered with the Has PC2. Quantitative PCR assay demonstrated that the Hdh PC2 was predominantly expressed in the pleuropedal ganglion rather than in other examined tissues. Although PC2 mRNA was expressed throughout the gametogenetic cycle of male and female abalone, the expression level was significantly higher in the ripening stage of female abalone. Also, a significantly higher expression was observed in the pleuropedal ganglion and gonadal tissues at a higher effective accumulative temperature (1000°C). In situ hybridization revealed that the PC2 mRNA expressing neurosecretory cells were distributed in the cortex region of the pleuropedal ganglion. According to the results, it can be concluded that pleuropedal ganglion is the highest site of PC2 activity, and this enzyme might be involved in the abalone reproduction process.
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Affiliation(s)
- Md Rajib Sharker
- Department of Fisheries Science, College of Fisheries and Ocean Sciences, Chonnam National University, Jeonnam, Republic of Korea
| | - Ill-Sup Nou
- Department of Horticulture, College of Life Science and Natural Resources, Sunchon National University, Jeollanam-do, Republic of Korea
| | - Kang Hee Kho
- Department of Fisheries Science, College of Fisheries and Ocean Sciences, Chonnam National University, Jeonnam, Republic of Korea
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9
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Caruana NJ, Strugnell JM, Finn J, Faou P, Plummer KM, Cooke IR. Quantitative Proteomic Analysis of the Slime and Ventral Mantle Glands of the Striped Pyjama Squid ( Sepioloidea lineolata). J Proteome Res 2020; 19:1491-1501. [PMID: 32091901 DOI: 10.1021/acs.jproteome.9b00738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Cephalopods are known to produce an extensive range of secretions including ink, mucus, and venom. Sepiadariidae, a family of small, benthic bobtail squids, are notable for the high volume of viscous slime they emit when stressed. One species, Sepioloidea lineolata (striped pyjama squid), is covered with glands along the perimeter of the ventral mantle, and these structures are hypothesized to be the source of its slime. Using label-free quantitative proteomics, we analyzed five tissue types (dorsal and ventral mantle muscle, dorsal and ventral epithelium, and ventral mantle glands) and the slime from four individuals. In doing so, we were able to determine the relationship between the slime and the tissues as well as highlight proteins that were specifically identified within the slime and ventral mantle glands. A total of 28 proteins were identified to be highly enriched in slime, and these were composed of peptidases and protease inhibitors. Seven of these proteins contained predicted signal peptides, indicating classical secretion, with four proteins having no identifiable domains or similarity to any known proteins. The ventral mantle glands also appear to be the tissue with the closest overall proteomic composition to the slime; therefore, it is likely that the slime originates, at least in part, from these glands.
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Affiliation(s)
- Nikeisha J Caruana
- Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Jan M Strugnell
- Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Victoria 3086, Australia.,Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville, Queensland 4811, Australia
| | - Julian Finn
- Sciences, Museums Victoria, Carlton, Victoria 3053, Australia
| | - Pierre Faou
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Kim M Plummer
- Department of Animal, Plant and Soil Sciences, AgriBio, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Ira R Cooke
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia.,Department of Molecular and Cell Biology, James Cook University, Townsville, Queensland 4811, Australia
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10
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Holst JJ, Albrechtsen NJW, Rosenkilde MM, Deacon CF. Physiology of the Incretin Hormones,
GIP
and
GLP
‐1—Regulation of Release and Posttranslational Modifications. Compr Physiol 2019; 9:1339-1381. [DOI: 10.1002/cphy.c180013] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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11
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Zhang Y, Xu C, Zhang H, Liu GD, Xue C, Cao Y. Targeting Hemagglutinin: Approaches for Broad Protection against the Influenza A Virus. Viruses 2019; 11:v11050405. [PMID: 31052339 PMCID: PMC6563292 DOI: 10.3390/v11050405] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 04/26/2019] [Accepted: 04/27/2019] [Indexed: 12/13/2022] Open
Abstract
Influenza A viruses are dynamically epidemic and genetically diverse. Due to the antigenic drift and shift of the virus, seasonal vaccines are required to be reformulated annually to match with current circulating strains. However, the mismatch between vaccinal strains and circulating strains occurs frequently, resulting in the low efficacy of seasonal vaccines. Therefore, several “universal” vaccine candidates based on the structure and function of the hemagglutinin (HA) protein have been developed to meet the requirement of a broad protection against homo-/heterosubtypic challenges. Here, we review recent novel constructs and discuss several important findings regarding the broad protective efficacy of HA-based universal vaccines.
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Affiliation(s)
- Yun Zhang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.
| | - Cong Xu
- Research Center of Agricultural of Dongguan City, Dongguan 523086, China.
| | - Hao Zhang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.
| | - George Dacai Liu
- Firstline Biopharmaceuticals Corporation, 12,050 167th PL NE, Redmond, WA 98052, USA.
| | - Chunyi Xue
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.
| | - Yongchang Cao
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.
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12
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Teitelman G. Heterogeneous Expression of Proinsulin Processing Enzymes in Beta Cells of Non-diabetic and Type 2 Diabetic Humans. J Histochem Cytochem 2019; 67:385-400. [PMID: 30759032 DOI: 10.1369/0022155419831641] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Although there is evidence indicating transcriptional and functional heterogeneity in human beta cells, it is unclear whether this heterogeneity extends to the expression level of the enzymes that process proinsulin to insulin in beta cells. To address this question, the expression levels of prohormone convertases (PC) 1/3, proprotein convertase 2 (PC2), and carboxypeptidase E (CPE) were determined in immune-stained sections of human pancreas. In non-diabetic donors, the level of proprotein convertase 1/3 (PC1/3) expression varied among beta cells of each islet but the average per islet was similar for all islets of each donor. Although the average PC1/3 expression of all islets examined per sample was unique for each pancreas, donors had similar levels of proinsulin/insulin expression. PC2 expression in beta cells showed less pronounced inter- and intraislet variation while CPE levels were fairly constant. The relationship between PC1/3 and PC2 expression levels was variable among different donors. Type 2 diabetes had an uneven effect on the expression levels of all three enzymes as they decrease only in some islets in a section. These findings suggest the presence of intraislet, but not interislet, variation in the expression of the proinsulin processing enzymes in non-diabetic subjects and a heterogeneous effect of type 2 diabetes on enzyme expression in islets.
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Affiliation(s)
- Gladys Teitelman
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York
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13
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Abstract
Sialic acid (Sia) is involved in many biological activities and commonly occurs as a monosialyl residue at the nonreducing terminal end of glycoconjugates. The loss of activity of UDP-GlcNAc2-epimerase/ManNAc kinase, which is a key enzyme in Sia biosynthesis, is lethal to the embryo, which clearly indicates the importance of Sia in embryogenesis. Occasionally, oligo/polymeric Sia structures such as disialic acid (diSia), oligosialic acid (oligoSia), and polysialic acid (polySia) occur in glycoconjugates. In particular, polySia, a well-known epitope that commonly occurs in neuroinvasive bacteria and vertebrate brains, is one of the most well-known and biologically/neurologically important glycotopes in vertebrates. The biological effects of polySia, especially on neural cell-adhesion molecules, have been well studied, and in-depth knowledge regarding polySia has been accumulated. In addition, the importance of diSia and oligoSia epitopes has been reported. In this chapter, the recent advances in the study of diSia, oligoSia, and polySia residues in glycoproteins in neurology, and their history, definition, occurrence, analytical methods, biosynthesis, and biological functions evaluated by phenotypes of gene-targeted mice, biochemical features, and related diseases are described.
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Holst JJ. From the Incretin Concept and the Discovery of GLP-1 to Today's Diabetes Therapy. Front Endocrinol (Lausanne) 2019; 10:260. [PMID: 31080438 PMCID: PMC6497767 DOI: 10.3389/fendo.2019.00260] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 04/08/2019] [Indexed: 12/24/2022] Open
Abstract
Researchers have been looking for insulin-stimulating factors for more than 100 years, and in the 1960ties it was definitively proven that the gastrointestinal tract releases important insulinotropic factors upon oral glucose intake, so-called incretin hormones. The first significant factor identified was the duodenal glucose-dependent insulinotropic polypeptide, GIP, which however, turned out not to stimulate insulin secretion in patients with type 2 diabetes. But resection experiments clearly indicated the presence of an additional incretin, and in 1986, an unexpected processing fragment of the recently identified glucagon precursor, proglucagon, namely truncated glucagon-like peptide 1 (GLP-1 7-36 amide), was isolated from the gut and found to both stimulate insulin secretion and inhibit glucagon secretion. The peptide also inhibited appetite and food intake. Unlike GIP, this peptide had preserved effects in patients with type 2 diabetes and it was soon documented to have powerful antidiabetic effects in clinical studies. Its utility was limited, however, because of an extremely short half-life in humans, but this problem had two solutions, both of which gave rise to important antidiabetic drugs: (1) orally active inhibitors of the enzyme dipeptidylpeptidase 4 (DPP-4 inhibitors), which was responsible for the rapid degradation; the inhibitors protect endogenous GLP-1 from degradation and thereby unfold its antidiabetic activity, and (2) long-acting injectable analogs of GLP-1 protected against DPP-4 degradation. Particularly, the latter, the GLP-1 receptor agonists, either alone or in various combinations, are so powerful that treatment allows more than 2/3 of type 2 diabetes patients to reach glycemic targets. In addition, these agents cause a weight loss which, with the most successful compounds, may exceed 10% of body weight. Most recently they have also been shown to be renoprotective and reduce cardiovascular risk and mortality.
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Protein Nanofibrils as Storage Forms of Peptide Drugs and Hormones. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1174:265-290. [PMID: 31713202 DOI: 10.1007/978-981-13-9791-2_8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Amyloids are highly organized cross β-sheet protein nanofibrils that are associated with both diseases and functions. Thermodynamically amyloids are stable structures as they represent the lowest free energy state that proteins can attain. However, recent studies suggest that amyloid fibrils can be dissociated by a change in environmental parameters such as pH and ionic strength. This reversibility of amyloids can not only be associated with disease, but function as well. In disease-associated amyloids, fibrils can act as reservoirs of cytotoxic oligomers. Recently, in higher organisms such as mammals, hormones were found to be stored in amyloid-like state, where these were reported to act as a reservoir of functional monomers. These hormone amyloids can dissociate to monomers upon release from the secretory granules, and subsequently bind to their respective receptors and perform their functions. In this book chapter, we describe in detail how these protein nanofibrils represent the densest possible peptide packing and are suitable for long-term storage. Thus, mimicking the feature of amyloids to release functional monomers, it is possible to formulate amyloid-based peptide/protein drugs, which can be used for sustained release.
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Complementary recognition of the receptor-binding site of highly pathogenic H5N1 influenza viruses by two human neutralizing antibodies. J Biol Chem 2018; 293:16503-16517. [PMID: 30154240 PMCID: PMC6200926 DOI: 10.1074/jbc.ra118.004604] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/03/2018] [Indexed: 01/07/2023] Open
Abstract
The highly pathogenic avian influenza virus H5N1 is a major threat to global public health and therefore a high-priority target of current vaccine development. The receptor-binding site (RBS) on the globular head of hemagglutinin (HA) in the viral envelope is one of the major target sites for antibody recognition against H5N1 and other influenza viruses. Here, we report the identification and characterization of a pair of human RBS-specific antibodies, designated FLD21.140 and AVFluIgG03, that are mutually complementary in their neutralizing activities against a diverse panel of H5N1 viruses. Crystallographic analysis and site-directed mutagenesis revealed that the two antibodies share a similar RBS-binding mode, and their individual specificities are governed by residues at positions 133a, 144, and 145. Specifically, FLD21.140 preferred Leu-133a/Lys-144/Ser-145, whereas AVFluIgG03 favored Ser-133a/Thr-144/Pro-145 residue triplets, both of which perfectly matched the most prevalent residues in viruses from epidemic-originating regions. Of note, according to an analysis of 3758 H5 HA sequences available in the Influenza Virus Database at the National Center for Biotechnology Information, the residues Leu-133a/Ser-133a and Ser-145/Pro-145 constituted more than 87.6 and 99.3% of all residues at these two positions, respectively. Taken together, our results provide a structural understanding for the neutralizing complementarity of these two antibodies and improve our understanding of the RBS-specific antibody response against H5N1 infection in humans.
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Salem JB, Nkambeu B, Arvanitis DN, Beaudry F. Deciphering the Role of EGL-3 for Neuropeptides Processing in Caenorhabditis elegans Using High-Resolution Quadrupole–Orbitrap Mass Spectrometry. Neurochem Res 2018; 43:2121-2131. [DOI: 10.1007/s11064-018-2636-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 09/07/2018] [Accepted: 09/10/2018] [Indexed: 01/13/2023]
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Kusunoki H, Tanaka T, Kohno T, Matsuhashi K, Hosoda K, Wakamatsu K, Hamaguchi I. A novel neuropilin-1-binding sequence in the human T-cell lymphotropic virus type 1 envelope glycoprotein. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:541-548. [PMID: 29458191 DOI: 10.1016/j.bbapap.2018.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 02/13/2018] [Accepted: 02/15/2018] [Indexed: 12/25/2022]
Abstract
Entry of human T-cell lymphotropic virus type 1 (HTLV-1) into host cells is mainly mediated by interactions between the viral envelope glycoprotein surface unit (SU) and three host receptors: glucose transporter type 1, heparin/heparan sulfate proteoglycan, and neuropilin-1 (Nrp1). Here, we analyzed the interaction between HTLV-1 SU and Nrp1 using nuclear magnetic resonance and isothermal titration calorimetry. We found that two SU peptides, residues 85-94 and residues 304-312, bound directly to the Nrp1 b1 domain with affinities of 7.4 and 17.7 μM, respectively. The binding modes of both peptides were almost identical to those observed for Tuftsin and vascular endothelial growth factor A binding to the Nrp1 b1 domain. These results suggest that the C-terminal region of HTLV-1 SU contains a novel site for direct binding of virus to the Nrp1 b1 domain. Our biophysical characterization of the SU peptides may help in developing inhibitors of HTLV-1 entry.
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Affiliation(s)
- Hideki Kusunoki
- Department of Safety Research on Blood and Biological Products, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan.
| | - Toshiyuki Tanaka
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Life Science Center, Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Toshiyuki Kohno
- Department of Biochemistry, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan
| | - Kazuhiko Matsuhashi
- Department of Safety Research on Blood and Biological Products, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan; Department of Pediatrics, The Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8666, Japan
| | - Kazuo Hosoda
- Department of Chemistry and Chemical Biology, Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Kaori Wakamatsu
- Department of Chemistry and Chemical Biology, Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Isao Hamaguchi
- Department of Safety Research on Blood and Biological Products, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan.
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Holst JJ, Albrechtsen NJW, Gabe MBN, Rosenkilde MM. Oxyntomodulin: Actions and role in diabetes. Peptides 2018; 100:48-53. [PMID: 29412831 DOI: 10.1016/j.peptides.2017.09.018] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 09/26/2017] [Accepted: 09/28/2017] [Indexed: 12/19/2022]
Abstract
Oxyntomodulin is a product of the glucagon precursor, proglucagon, produced and released from the endocrine L-cells of the gut after enzymatic processing by the precursor prohormone convertase 1/3. It corresponds to the proglucagon sequence 33-69 and thus contains the entire glucagon sequence plus a C-terminal octapeptide, comprising in total 37 amino acids. As might have been expected, it has glucagon-like bioactivity, but also and more surprisingly also activates the receptor for GLP-1. This has given the molecule an interesting status as a glucagon-GLP-1 co-agonist, which is currently attracting considerable interest for its potential in the treatment of diabetes and obesity. Here, we provide an update on oxyntomodulin with a focus on its potential role in metabolic diseases.
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Affiliation(s)
- Jens J Holst
- Department of Biomedical Sciences & Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Nicolai J Wewer Albrechtsen
- Department of Biomedical Sciences & Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maria Buur Nordskov Gabe
- Department of Biomedical Sciences & Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette Marie Rosenkilde
- Department of Biomedical Sciences & Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Giesselmann E, Becker B, Schmitt MJ. Production of fluorescent and cytotoxic K28 killer toxin variants through high cell density fermentation of recombinant Pichia pastoris. Microb Cell Fact 2017; 16:228. [PMID: 29258515 PMCID: PMC5735513 DOI: 10.1186/s12934-017-0844-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 12/13/2017] [Indexed: 01/29/2023] Open
Abstract
Background Virus infected killer strains of the baker’s yeast Saccharomyces cerevisiae secrete protein toxins such as K28, K1, K2 and Klus which are lethal to sensitive yeast strains of the same or related species. K28 is somewhat unique as it represents an α/β heterodimeric protein of the A/B toxin family which, after having bound to the surface of sensitive target cells, is taken up by receptor-mediated endocytosis and transported through the secretory pathway in a retrograde manner. While the current knowledge on yeast killer toxins is largely based on genetic screens for yeast mutants with altered toxin sensitivity, in vivo imaging of cell surface binding and intracellular toxin transport is still largely hampered by a lack of fluorescently labelled and biologically active killer toxin variants. Results In this study, we succeeded for the first time in the heterologous K28 preprotoxin expression and production of fluorescent K28 variants in Pichia pastoris. Recombinant P. pastoris GS115 cells were shown to successfully process and secrete K28 variants fused to mCherry or mTFP by high cell density fermentation. The fluorescent K28 derivatives were obtained in high yield and possessed in vivo toxicity and specificity against sensitive yeast cells. In cell binding studies the resulting K28 variants caused strong fluorescence signals at the cell periphery due to toxin binding to primary K28 receptors within the yeast cell wall. Thereby, the β-subunit of K28 was confirmed to be the sole component required and sufficient for K28 cell wall binding. Conclusion Successful production of fluorescent killer toxin variants of S. cerevisiae by high cell density fermentation of recombinant, K28 expressing strains of P. pastoris now opens the possibility to study and monitor killer toxin cell surface binding, in particular in toxin resistant yeast mutants in which toxin resistance is caused by defects in toxin binding due to alterations in cell wall structure and composition. This novel approach might be easily transferable to other killer toxins from different yeast species and genera. Furthermore, the fluorescent toxin variants described here might likewise represent a powerful tool in future studies to visualize intracellular A/B toxin trafficking with the help of high resolution single molecule imaging techniques.
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Affiliation(s)
- Esther Giesselmann
- Molecular and Cell Biology, Department of Biosciences and Center of Human and Molecular Biology (ZHMB), Saarland University, 66123, Saarbrücken, Germany
| | - Björn Becker
- Molecular and Cell Biology, Department of Biosciences and Center of Human and Molecular Biology (ZHMB), Saarland University, 66123, Saarbrücken, Germany
| | - Manfred J Schmitt
- Molecular and Cell Biology, Department of Biosciences and Center of Human and Molecular Biology (ZHMB), Saarland University, 66123, Saarbrücken, Germany.
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Antunes AA, Jesus LDOP, Manfredi MA, de Souza AA, Machado MFM, E Silva PM, Icimoto MY, Juliano MA, Juliano L, Judice WADS. Thermodynamic analysis of Kex2 activity: The acylation and deacylation steps are potassium- and substrate-dependent. Biophys Chem 2017; 235:29-39. [PMID: 29432900 DOI: 10.1016/j.bpc.2017.11.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/30/2017] [Accepted: 11/30/2017] [Indexed: 01/15/2023]
Abstract
Kex2 is the prototype of a large family of eukaryotic subtilisin-related proprotein-processing proteases that cleave at sites containing pairs of basic residues. Here, we studied the effects of KCl on the individual rate constants of association, dissociation, acylation and deacylation and determined the thermodynamic parameters at each step of the Kex2 reaction. Potassium bound Kex2 with KD=20.3mM. The order in which potassium entered the reaction system modified the effect of activation or inhibition, which depended on the size of the substrate. A possible allosteric potassium binding site at the S6 subsite was involved in activation, and a distant site located between the catalytic domain and the P-domain was involved in inhibition. Potassium decreased the energetic barriers of almost all steps of catalysis. The acylation of Ac-PMYKR-AMC in the absence of potassium was the rate-limiting step. Therefore, for substrates containing a P1-Arg, the deacylation step is not necessarily the rate-limiting event, and other residues at the P' positions may participate in controlling the acylation and deacylation steps. Thus, it is reasonable to conclude that potassium is involved in the processing of the α-mating factor that promotes Ca2+ mobilization by activating a high-affinity Ca2+-influx system to increase the cytosolic [Ca2+], resulting in the activation of channels that are essential for the survival of Saccharomyces cerevisiae cells.
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Affiliation(s)
- Alyne Alexandrino Antunes
- Centro Interdisciplinar de Investigação Bioquímica, Universidade de Mogi das Cruzes - UMC, Av. Cândido Xavier de Almeida e Souza, 200, Sala 1S-15, Vila Partênio, CEP: 08780-911 Mogi das Cruzes, SP, Brazil
| | - Larissa de Oliveira Passos Jesus
- Centro Interdisciplinar de Investigação Bioquímica, Universidade de Mogi das Cruzes - UMC, Av. Cândido Xavier de Almeida e Souza, 200, Sala 1S-15, Vila Partênio, CEP: 08780-911 Mogi das Cruzes, SP, Brazil
| | - Marcella Araújo Manfredi
- Centro Interdisciplinar de Investigação Bioquímica, Universidade de Mogi das Cruzes - UMC, Av. Cândido Xavier de Almeida e Souza, 200, Sala 1S-15, Vila Partênio, CEP: 08780-911 Mogi das Cruzes, SP, Brazil
| | - Aline Aparecida de Souza
- Centro Interdisciplinar de Investigação Bioquímica, Universidade de Mogi das Cruzes - UMC, Av. Cândido Xavier de Almeida e Souza, 200, Sala 1S-15, Vila Partênio, CEP: 08780-911 Mogi das Cruzes, SP, Brazil
| | - Maurício Ferreira Marcondes Machado
- Centro Interdisciplinar de Investigação Bioquímica, Universidade de Mogi das Cruzes - UMC, Av. Cândido Xavier de Almeida e Souza, 200, Sala 1S-15, Vila Partênio, CEP: 08780-911 Mogi das Cruzes, SP, Brazil
| | - Pamela Moraes E Silva
- Centro Interdisciplinar de Investigação Bioquímica, Universidade de Mogi das Cruzes - UMC, Av. Cândido Xavier de Almeida e Souza, 200, Sala 1S-15, Vila Partênio, CEP: 08780-911 Mogi das Cruzes, SP, Brazil
| | - Marcelo Yudi Icimoto
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio, 100, São Paulo, SP 04044-020, Brazil
| | - Maria Aparecida Juliano
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio, 100, São Paulo, SP 04044-020, Brazil
| | - Luiz Juliano
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio, 100, São Paulo, SP 04044-020, Brazil
| | - Wagner Alves de Souza Judice
- Centro Interdisciplinar de Investigação Bioquímica, Universidade de Mogi das Cruzes - UMC, Av. Cândido Xavier de Almeida e Souza, 200, Sala 1S-15, Vila Partênio, CEP: 08780-911 Mogi das Cruzes, SP, Brazil.
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Loss of mTORC1 signalling impairs β-cell homeostasis and insulin processing. Nat Commun 2017; 8:16014. [PMID: 28699639 PMCID: PMC5510183 DOI: 10.1038/ncomms16014] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 05/22/2017] [Indexed: 12/15/2022] Open
Abstract
Deregulation of mTOR complex 1 (mTORC1) signalling increases the risk for metabolic diseases, including type 2 diabetes. Here we show that β-cell-specific loss of mTORC1 causes diabetes and β-cell failure due to defects in proliferation, autophagy, apoptosis and insulin secretion by using mice with conditional (βraKO) and inducible (MIP-βraKOf/f) raptor deletion. Through genetic reconstitution of mTORC1 downstream targets, we identify mTORC1/S6K pathway as the mechanism by which mTORC1 regulates β-cell apoptosis, size and autophagy, whereas mTORC1/4E-BP2-eIF4E pathway regulates β-cell proliferation. Restoration of both pathways partially recovers β-cell mass and hyperglycaemia. This study also demonstrates a central role of mTORC1 in controlling insulin processing by regulating cap-dependent translation of carboxypeptidase E in a 4EBP2/eIF4E-dependent manner. Rapamycin treatment decreases CPE expression and insulin secretion in mice and human islets. We suggest an important role of mTORC1 in β-cells and identify downstream pathways driving β-cell mass, function and insulin processing. Deregulation of mTORC1 pathway has been associated with several human diseases including diabetes, neurodegeneration and cancer. Here Blandino-Rosano et al. show that mTORC1 signalling controls insulin secretion and β-cell maintenance by regulation of β-cell proliferation, apoptosis and autophagy and insulin processing.
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Wu NC, Wilson IA. A Perspective on the Structural and Functional Constraints for Immune Evasion: Insights from Influenza Virus. J Mol Biol 2017. [PMID: 28648617 DOI: 10.1016/j.jmb.2017.06.015] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Influenza virus evolves rapidly to constantly escape from natural immunity. Most humoral immune responses to influenza virus target the hemagglutinin (HA) glycoprotein, which is the major antigen on the surface of the virus. The HA is composed of a globular head domain for receptor binding and a stem domain for membrane fusion. The major antigenic sites of HA are located in the globular head subdomain, which is highly tolerant of amino acid substitutions and continual addition of glycosylation sites. Nonetheless, the evolution of the receptor-binding site and the stem region on HA is severely constrained by their functional roles in engaging the host receptor and in mediating membrane fusion, respectively. Here, we review how broadly neutralizing antibodies (bnAbs) exploit these evolutionary constraints to protect against diverse influenza strains. We also discuss the emerging role of other epitopes that are conserved only in subsets of viruses. This rapidly increasing knowledge of the evolutionary biology, immunology, structural biology, and virology of influenza virus is invaluable for development and design of more universal influenza vaccines and novel therapeutics.
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Affiliation(s)
- Nicholas C Wu
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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Dose-dependent effect of Bisphenol-A on insulin signaling molecules in cardiac muscle of adult male rat. Chem Biol Interact 2017; 266:10-16. [DOI: 10.1016/j.cbi.2017.01.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/20/2017] [Accepted: 01/26/2017] [Indexed: 01/16/2023]
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Dore R, Levata L, Lehnert H, Schulz C. Nesfatin-1: functions and physiology of a novel regulatory peptide. J Endocrinol 2017; 232:R45-R65. [PMID: 27754932 DOI: 10.1530/joe-16-0361] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 10/17/2016] [Indexed: 12/12/2022]
Abstract
Nesfatin-1 was identified in 2006 as a potent anorexigenic peptide involved in the regulation of homeostatic feeding. It is processed from the precursor-peptide NEFA/nucleobindin 2 (NUCB2), which is expressed both in the central nervous system as well as in the periphery, from where it can access the brain via non-saturable transmembrane diffusion. In hypothalamus and brainstem, nesfatin-1 recruits the oxytocin, the melancortin and other systems to relay its anorexigenic properties. NUCB2/nesfatin-1 peptide expression in reward-related areas suggests that nesfatin-1 might also be involved in hedonic feeding. Besides its initially discovered anorexigenic properties, over the last years, other important functions of nesfatin-1 have been discovered, many of them related to energy homeostasis, e.g. energy expenditure and glucose homeostasis. Nesfatin-1 is not only affecting these physiological processes but also the alterations of the metabolic state (e.g. fat mass, glycemic state) have an impact on the synthesis and release of NUCB2 and/or nesfatin-1. Furthermore, nesfatin-1 exerts pleiotropic actions at the level of cardiovascular and digestive systems, as well as plays a role in stress response, behavior, sleep and reproduction. Despite the recent advances in nesfatin-1 research, a putative receptor has not been identified and furthermore potentially distinct functions of nesfatin-1 and its precursor NUCB2 have not been dissected yet. To tackle these open questions will be the major objectives of future research to broaden our knowledge on NUCB2/nesfatin-1.
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Affiliation(s)
- Riccardo Dore
- Department of Internal Medicine ICenter of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Luka Levata
- Department of Internal Medicine ICenter of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Hendrik Lehnert
- Department of Internal Medicine ICenter of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Carla Schulz
- Department of Internal Medicine ICenter of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
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Releasing Mechanism of Neurotrophic Factors via Polysialic Acid. VITAMINS AND HORMONES 2017; 104:89-112. [DOI: 10.1016/bs.vh.2016.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Nillni EA. The metabolic sensor Sirt1 and the hypothalamus: Interplay between peptide hormones and pro-hormone convertases. Mol Cell Endocrinol 2016; 438:77-88. [PMID: 27614022 DOI: 10.1016/j.mce.2016.09.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 09/05/2016] [Accepted: 09/05/2016] [Indexed: 01/11/2023]
Abstract
The last decade had witnessed a tremendous progress in our understanding of the causes of metabolic diseases including obesity. Among the contributing factors regulating energy balance are nutrient sensors such as sirtuins. Sirtuin1 (Sirt1), a NAD + - dependent deacetylase is affected by diet, environmental stress, and also plays a critical role in metabolic health by deacetylating proteins in many tissues, including liver, muscle, adipose tissue, heart, endothelium, and in the complexity of the hypothalamus. Because of its dependence on NAD+, Sirt1 also functions as a nutrient/redox sensor, and new novel data show a function of this enzyme in the maturation of hypothalamic peptide hormones controlling energy balance either through regulation of specific nuclear transcription factors or by regulating specific pro-hormone convertases (PCs) involved in the post-translational processing of pro-hormones. The post-translational processing mechanism of pro-hormones is critical in the pathogenesis of obesity as recently shown that metabolic and physiological triggers affect the biosynthesis and processing of many peptides hormones. Specific regulation of pro-hormone processing is likely another key step where final amounts of bioactive peptides can be tightly regulated. Different factors stimulate or inhibit pro-hormones biosynthesis in concert with an increase in the PCs involved in the maturation of bioactive hormones. Adding more complexity to the system, the new studies describe here suggest that Sirt1 could also regulate the fate of peptide hormone biosynthesis. The present review summarizes the recent progress in hypothalamic SIRT1 research with a particular emphasis on the tissue-specific control of neuropeptide hormone maturation. The series of studies done in mouse and rat models strongly advocate for the first time that a deacetylating enzyme could be a regulator in the maturation of peptide hormones and their processing enzymes. These discoveries are the culmination of the first in-depth understanding of the metabolic role of Sirt1 in the brain. It suggests that Sirt1 behaves differently in the brain than in organs such as the liver and pancreas, where the enzyme has been more commonly studied.
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Affiliation(s)
- Eduardo A Nillni
- The Warren Alpert Medical School, Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA.
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Ecuador Paraiso Escondido Virus, a New Flavivirus Isolated from New World Sand Flies in Ecuador, Is the First Representative of a Novel Clade in the Genus Flavivirus. J Virol 2015; 89:11773-85. [PMID: 26355096 PMCID: PMC4645344 DOI: 10.1128/jvi.01543-15] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/04/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED A new flavivirus, Ecuador Paraiso Escondido virus (EPEV), named after the village where it was discovered, was isolated from sand flies (Psathyromyia abonnenci, formerly Lutzomyia abonnenci) that are unique to the New World. This represents the first sand fly-borne flavivirus identified in the New World. EPEV exhibited a typical flavivirus genome organization. Nevertheless, the maximum pairwise amino acid sequence identity with currently recognized flaviviruses was 52.8%. Phylogenetic analysis of the complete coding sequence showed that EPEV represents a distinct clade which diverged from a lineage that was ancestral to the nonvectored flaviviruses Entebbe bat virus, Yokose virus, and Sokoluk virus and also the Aedes-associated mosquito-borne flaviviruses, which include yellow fever virus, Sepik virus, Saboya virus, and others. EPEV replicated in C6/36 mosquito cells, yielding high infectious titers, but failed to reproduce either in vertebrate cell lines (Vero, BHK, SW13, and XTC cells) or in suckling mouse brains. This surprising result, which appears to eliminate an association with vertebrate hosts in the life cycle of EPEV, is discussed in the context of the evolutionary origins of EPEV in the New World. IMPORTANCE The flaviviruses are rarely (if ever) vectored by sand fly species, at least in the Old World. We have identified the first representative of a sand fly-associated flavivirus, Ecuador Paraiso Escondido virus (EPEV), in the New World. EPEV constitutes a novel clade according to current knowledge of the flaviviruses. Phylogenetic analysis of the virus genome showed that EPEV roots the Aedes-associated mosquito-borne flaviviruses, including yellow fever virus. In light of this new discovery, the New World origin of EPEV is discussed together with that of the other flaviviruses.
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Yamamoto H, Iguchi K, Unno K, Kaji K, Hoshino M. Expression and release of progalanin in fibroblasts. ACTA ACUST UNITED AC 2014; 194-195:55-62. [DOI: 10.1016/j.regpep.2014.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 09/03/2014] [Accepted: 09/06/2014] [Indexed: 11/30/2022]
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Molecular-based identification and phylogeny of genomic and proteomic sequences of mosquito-borne flavivirus. Genes Genomics 2013. [DOI: 10.1007/s13258-013-0137-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
Saccharomyces cerevisiae has been a key experimental organism for the study of infectious diseases, including dsRNA viruses, ssRNA viruses, and prions. Studies of the mechanisms of virus and prion replication, virus structure, and structure of the amyloid filaments that are the basis of yeast prions have been at the forefront of such studies in these classes of infectious entities. Yeast has been particularly useful in defining the interactions of the infectious elements with cellular components: chromosomally encoded proteins necessary for blocking the propagation of the viruses and prions, and proteins involved in the expression of viral components. Here, we emphasize the L-A dsRNA virus and its killer-toxin-encoding satellites, the 20S and 23S ssRNA naked viruses, and the several infectious proteins (prions) of yeast.
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Liu SH, Huang YW, Wu CT, Chiu CY, Chiang MT. Low molecular weight chitosan accelerates glucagon-like peptide-1 secretion in human intestinal endocrine cells via a p38-dependent pathway. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2013; 61:4855-4861. [PMID: 23611362 DOI: 10.1021/jf305410k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Chitosan is widely employed as a dietary supplement. Several studies have shown that chitosan possesses an antidiabetic effect. An important intestinal incretin hormone, glucagon-like peptide-1 (GLP-1), is also known to contribute to the amelioration of diabetes. This study investigated whether chitosan possesses an ability in GLP-1 synthesis and secretion in human intestinal cells. Low molecular weight chitosan (LMWC) significantly increases GLP-1 secretion in human intestinal endocrine cells (NCI-H716) in a dose-dependent manner. LMWC could also dose-dependently increase the mRNA expression of proglucagon, a GLP-1 precursor, but did not affect prohormone convertase 3 (PC 3) mRNA expression. LMWC effectively increased the phosphorylation of mitogen-activated protein kinases (MAPK)-p38 and c-Jun N-terminal kinases (JNK), but not extracellular-signal-regulated kinases (ERK). An inhibitor of p38, but not JNK and ERK, significantly reversed the LMWC-increased proglucagon expression. Taken together, LMWC accelerates proglucagon expression and GLP-1 secretion through a p38/MAPK-dependent signaling pathway. These findings suggest that LMWC may provide a strategy for diabetes therapy.
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Affiliation(s)
- Shing Hwa Liu
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
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TBC-8, a putative RAB-2 GAP, regulates dense core vesicle maturation in Caenorhabditis elegans. PLoS Genet 2012; 8:e1002722. [PMID: 22654674 PMCID: PMC3359978 DOI: 10.1371/journal.pgen.1002722] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 04/04/2012] [Indexed: 02/05/2023] Open
Abstract
Dense core vesicles (DCVs) are thought to be generated at the late Golgi apparatus as immature DCVs, which subsequently undergo a maturation process through clathrin-mediated membrane remodeling events. This maturation process is required for efficient processing of neuropeptides within DCVs and for removal of factors that would otherwise interfere with DCV release. Previously, we have shown that the GTPase, RAB-2, and its effector, RIC-19, are involved in DCV maturation in Caenorhabditis elegans motoneurons. In rab-2 mutants, specific cargo is lost from maturing DCVs and missorted into the endosomal/lysosomal degradation route. Cargo loss could be prevented by blocking endosomal delivery. This suggests that RAB-2 is involved in retention of DCV components during the sorting process at the Golgi-endosomal interface. To understand how RAB-2 activity is regulated at the Golgi, we screened for RAB-2-specific GTPase activating proteins (GAPs). We identified a potential RAB-2 GAP, TBC-8, which is exclusively expressed in neurons and which, when depleted, shows similar DCV maturation defects as rab-2 mutants. We could demonstrate that RAB-2 binds to its putative GAP, TBC-8. Interestingly, TBC-8 also binds to the RAB-2 effector, RIC-19. This interaction appears to be conserved as TBC-8 also interacted with the human ortholog of RIC-19, ICA69. Therefore, we propose that a dynamic ON/OFF cycling of RAB-2 at the Golgi induced by the GAP/effector complex is required for proper DCV maturation.
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Affiliation(s)
- Reed B Wickner
- Laboratory of Biochemistry and Genetics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0830, USA.
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The multibasic cleavage site of the hemagglutinin of highly pathogenic A/Vietnam/1203/2004 (H5N1) avian influenza virus acts as a virulence factor in a host-specific manner in mammals. J Virol 2011; 86:2706-14. [PMID: 22205751 DOI: 10.1128/jvi.05546-11] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Highly pathogenic avian influenza (HPAI) viruses of the H5 and H7 subtypes typically possess multiple basic amino acids around the cleavage site (MBS) of their hemagglutinin (HA) protein, a recognized virulence motif in poultry. To determine the importance of the H5 HA MBS as a virulence factor in mammals, recombinant wild-type HPAI A/Vietnam/1203/2004 (H5N1) viruses that possessed (H5N1) or lacked (ΔH5N1) the H5 HA MBS were generated and evaluated for their virulence in BALB/c mice, ferrets, and African green monkeys (AGMs) (Chlorocebus aethiops). The presence of the H5 HA MBS was associated with lethality, significantly higher virus titers in the respiratory tract, virus dissemination to extrapulmonary organs, lymphopenia, significantly elevated levels of proinflammatory cytokines and chemokines, and inflammation in the lungs of mice and ferrets. In AGMs, neither H5N1 nor ΔH5N1 virus was lethal and neither caused clinical symptoms. The H5 HA MBS was associated with mild enhancement of replication and delayed virus clearance. Thus, the contribution of H5 HA MBS to the virulence of the HPAI H5N1 virus varies among mammalian hosts and is most significant in mice and ferrets and less remarkable in nonhuman primates.
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Affiliation(s)
- Godfrey S Getz
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA.
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Peng J, Jiang J, Wang W, Qi X, Sun XL, Wu Q. Glycosylation and processing of pro-B-type natriuretic peptide in cardiomyocytes. Biochem Biophys Res Commun 2011; 411:593-8. [PMID: 21763278 DOI: 10.1016/j.bbrc.2011.06.192] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 06/30/2011] [Indexed: 10/18/2022]
Abstract
B-type natriuretic peptide (BNP) and its related peptides are biomarkers for the diagnosis of heart failure. Recent studies identified several O-glycosylation sites, including Thr-71, on human pro-BNP but the functional significance was unclear. In this study, we analyzed glycosylation and proteolytic processing of pro-BNP in cardiomyocytes. Human pro-BNP wild-type (WT) and mutants were expressed in HEK 293 cells and murine HL-1 cardiomyocytes. Pro-BNP and BNP were analyzed by immunoprecipitation and Western blotting. Glycosidases and glycosylation inhibitors were used to examine carbohydrates on pro-BNP. The effects of furin and corin expression on pro-BNP processing in cells also were examined. We found that in HEK 293 cells, recombinant pro-BNP contained significant amounts of O-glycans with terminal oligosialic acids. Mutation at Thr-71 reduced O-glycans on pro-BNP and increased pro-BNP processing. In HL-1 cardiomyocytes, residue Thr-71 contained little O-glycans, and pro-BNP WT and T71A mutant were processed similarly. In HEK 293 cells, pro-BNP was processed by furin. Mutations at Arg-73 and Arg-76, but not Lys-79, prevented pro-BNP processing. In HL-1 cardiomyocytes, which express furin and corin, single or double mutations at Arg-73, Arg-76 and Lys-79 did not prevent pro-BNP processing. Only when all these three residues were mutated, was pro-BNP processing completely blocked. Our data indicate that pro-BNP glycosylation in cardiomyocytes differed significantly from that in HEK 293 cells. In HEK 293 cells, furin cleaved pro-BNP at Arg-76 whereas in cardiomyocytes corin cleaved pro-BNP at multiple residues including Arg-73, Arg-76 and Lys-79.
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Affiliation(s)
- Jianhao Peng
- Molecular Cardiology, Nephrology and Hypertension, Cleveland Clinic, Cleveland, OH, United States
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Abstract
Insulin is a small but beautifully organized protein with a unique two-chain structure, the first protein to be sequenced. The mechanism of its biosynthesis invited much initial speculation but was finally clarified by the discovery of proinsulin, its single-chain precursor. The rich present-day field of protein precursor processing via post-translational proteolysis within the secretory pathway arose in the early 1970s as an offshoot of studies on insulin biosynthesis, which provided a novel paradigm for the generation of many other small neuroendocrine peptides. Before long, this mechanism was also found to play a role in the production of a much wider spectrum of proteins traversing the secretory pathway (receptors, growth factors, blood-clotting components, and even many viral envelope proteins) occurring in almost all eukaryotic cells. Indeed, yeast provided a key clue in the search for the proprotein convertases, the endoproteases that work along with carboxypeptidases and other modifying enzymes, such as the amidating enzyme complex (PAM), in converting inactive or less active precursor proteins into their fully active peptide products. In this "Reflections" article, I have tried to recount the people and events in my life that led to my involvement first in basic biochemical research and then on to insulin, proinsulin, and many relevant related areas that continue to fascinate and challenge my colleagues and me, as well as many other biomedical scientists today, as diabetes mellitus increasingly threatens human health throughout our contemporary world.
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Affiliation(s)
- Donald F Steiner
- Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA.
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Helwig M, Vivoli M, Fricker LD, Lindberg I. Regulation of neuropeptide processing enzymes by catecholamines in endocrine cells. Mol Pharmacol 2011; 80:304-13. [PMID: 21540292 DOI: 10.1124/mol.111.072090] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Treatment of cultured bovine adrenal chromaffin cells with the catecholamine transport blocker reserpine was shown previously to increase enkephalin levels severalfold. To explore the biochemical mechanism of this effect, we examined the effect of reserpine treatment on the activities of three different peptide precursor processing enzymes: carboxypeptidase E (CPE) and the prohormone convertases (PCs) PC1/3 and PC2. Reserpine treatment increased both CPE and PC activity in extracts of cultured chromaffin cells; total protein levels were unaltered for any enzyme. Further analysis showed that the increase in CPE activity was due to an elevated V(max), with no change in the K(m) for substrate hydrolysis or the levels of CPE mRNA. Reserpine activation of endogenous processing enzymes was also observed in extracts prepared from PC12 cells stably expressing PC1/3 or PC2. In vitro experiments using purified enzymes showed that catecholamines inhibited CPE, PC1/3, and PC2, with dopamine quinone the most potent inhibitor (IC(50) values of ∼50-500 μM); dopamine, norepinephrine, and epinephrine exhibited inhibition in the micromolar range. The inhibition of purified CPE with catecholamines was time-dependent and, for dopamine quinone, dilution-independent, suggesting covalent modification of the protein by the catecholamine. Because the catecholamine concentrations found to be inhibitory to PC1/3, PC2, and CPE are well within the physiological range found in chromaffin granules, we conclude that catecholaminergic transmitter systems have the potential to exert considerable dynamic influence over peptidergic transmitter synthesis by altering the activity of peptide processing enzymes.
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Affiliation(s)
- Michael Helwig
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn Street, Baltimore, MD 21201, USA
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Abstract
The initial discovery of leptin, an appetite-suppressing hormone originating from fat tissue, substantially supported the idea that fat-borne factors act on the brain to regulate food intake and energy expenditure. Since then, a growing number of cytokines have been found to be released from adipose tissue, thus acting in an endocrine manner. These adipocytokines include not only, e.g., adiponectin, apelin, resistin, and visfatin, but also inflammatory cytokines and steroid hormones such as estrogens and glucocorticoids. They are secreted from their adipose depots and differ in terms of release stimuli, downstream signaling, and their action on the brain. Clearly, adipocytokines play a prominent role in the central control of body weight, and the deregulation of this circuit may lead to the development of obesity and related disorders. In this chapter, we will focus on crosstalk mechanisms and the deregulation of adipocytokines at the expression level and/or sites of central action that eventually will lead to the development and perpetuation of obesity and diabetes.
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Affiliation(s)
- Carla Schulz
- Department of Internal Medicine I, Luebeck University, Ratzeburger Allee 160, 23538 Luebeck, Germany
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Patel YC, Liu J, Galanopoulou A, Papachristou DN. Production, Action, and Degradation of Somatostatin. Compr Physiol 2011. [DOI: 10.1002/cphy.cp070209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Kögel T, Rudolf R, Hodneland E, Hellwig A, Kuznetsov SA, Seiler F, Söllner TH, Barroso J, Gerdes HH. Distinct Roles of Myosin Va in Membrane Remodeling and Exocytosis of Secretory Granules. Traffic 2010; 11:637-50. [DOI: 10.1111/j.1600-0854.2010.01048.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Othman R, Nuraziyan A. Fruit-specific expression of papaya subtilase gene. JOURNAL OF PLANT PHYSIOLOGY 2010; 167:131-7. [PMID: 19729222 DOI: 10.1016/j.jplph.2009.07.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Revised: 07/27/2009] [Accepted: 07/28/2009] [Indexed: 05/09/2023]
Abstract
Subtilisin-like serine proteases (EC 3.4.21) consist of a widespread family of enzymes that is involved in various processes including in plants. The full-length cDNA (CpSUB1) and the corresponding genomic DNA for papaya subtilase have been obtained using rapid amplification of cDNA ends (RACEs) and PCR primer walking techniques, respectively. The cDNA clone contains an open reading frame of 2316bp encoding 772 amino acids with a calculated molecular mass of 82.6kDa and an isoelectric point (pI) of 8.97. The CpSUB1 gene is composed of nine exons and eight introns. The amino acid sequence encoded by CpSUB1 shared high identity (>60%) with the amino acid sequence of other plant subtilisin-like proteases. Sequence analysis of CpSUB1 revealed the presence of a possible signal peptide (25 amino acid residues) and an NH(2)-terminal prosequence (88 amino acid residues). In addition, papaya subtilase possesses the characteristic subtilisin catalytic triad amino acids namely Asp, His and Ser, together with the substrate-binding site, Asn. DNA hybridization analysis showed that subtilase gene exists as a single copy in the papaya genome. RNA hybridization analyses showed that expression of the subtilase transcripts was only detected in mesocarp but not in non-fruit tissues. Gene expression in fruit tissues reached the highest level during the ripening stage at which the fruits undergo dramatic softening process. Subsequently, pro-subtilase ( approximately 80kDa) was expressed as recombinant pro-enzyme ( approximately 97kDa), which was used to generate antiserum against papaya subtilase, anti-sub. Protein gel blot analysis using anti-sub towards total protein extracted from all ripening stages revealed that a protein with a molecular mass of approximately 70kDa reacted with the antiserum. Hence both RNA hybridization and protein gel blot analyses confirmed the presence of subtilase during papaya fruit ripening, pointing to its possible involvement in this important process.
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Affiliation(s)
- Roohaida Othman
- Centre for Gene Analysis and Technology, Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan, Malaysia.
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Kudo H, Liu J, Jansen EJR, Ozawa A, Panula P, Martens GJM, Lindberg I. Identification of proSAAS homologs in lower vertebrates: conservation of hydrophobic helices and convertase-inhibiting sequences. Endocrinology 2009; 150:1393-9. [PMID: 18948394 PMCID: PMC2654743 DOI: 10.1210/en.2008-1301] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The prohormone convertases (PCs) 1/3 and 2 accomplish the major proteolytic cleavage events in neuroendocrine tissues; each of these convertases has a small associated binding protein that inhibits convertase action in the secretory pathway. The proSAAS protein binds to PC1/3, whereas the 7B2 protein binds to PC2. However, both convertase-binding proteins are more widely expressed than their cognate enzymes, suggesting that they may perform other functions as well. All known mammalian proSAASs are over 85% conserved; thus, identifying functionally important segments has been impossible. Here, we report the first identification of nonmammalian proSAAS molecules, from Xenopus and zebrafish (Danio rerio). Although these two proteins show an overall amino acid sequence identity of only 29 and 30% with mouse proSAAS, two 14-16 residue hydrophobic segments (predicted to form alpha-helices) and two, nine through 11 residue sequences containing basic convertase cleavage sites are highly conserved; therefore, these sequences may be of functional importance. Confidence that these nonmammalian molecules represent authentic proSAAS is supported by the finding that both inhibit mouse PC1/3 with nanomolar inhibition constants; human furin was not inhibited. In vitro, the two proteins were cleaved by PC2 and furin to three or more peptide products. Both zebrafish and Xenopus proSAAS exhibited neural and endocrine distributions, as assessed by in situ and PCR experiments, respectively. In summary, the identification of proSAAS molecules in lower vertebrates provides clues as to functional regions within this widely expressed neuroendocrine protein.
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Affiliation(s)
- H Kudo
- Department of Anatomy and Neurobiology, University of Maryland-Baltimore, Baltimore, Maryland 21201, USA
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Kagawa TF, O'Connell MR, Mouat P, Paoli M, O'Toole PW, Cooney JC. Model for Substrate Interactions in C5a Peptidase from Streptococcus pyogenes: A 1.9 Å Crystal Structure of the Active Form of ScpA. J Mol Biol 2009; 386:754-72. [DOI: 10.1016/j.jmb.2008.12.074] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 12/18/2008] [Accepted: 12/29/2008] [Indexed: 10/21/2022]
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Establishment of retroviral pseudotypes with influenza hemagglutinins from H1, H3, and H5 subtypes for sensitive and specific detection of neutralizing antibodies. J Virol Methods 2008; 153:111-9. [DOI: 10.1016/j.jviromet.2008.07.015] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2008] [Revised: 07/15/2008] [Accepted: 07/23/2008] [Indexed: 01/23/2023]
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Rholam M, Brakch N, Germain D, Thomas DY, Fahy C, Boussetta H, Boileau G, Cohen P. Role of Amino Acid Sequences Flanking Dibasic Cleavage Sites in Precursor Proteolytic Processing. ACTA ACUST UNITED AC 2008. [DOI: 10.1111/j.1432-1033.1995.0707p.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Zakutskiĭ AN, Chalisova NI, Subbotina TF. [Functional arginine-containing amino acid sequences in peptides and proteins]. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2008; 34:149-59. [PMID: 18522270 DOI: 10.1134/s1068162008020015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
L-arginine is a source of nitrogen oxide and plays a great role in a number of other biochemical processes. Functions and prospects for practical application of five groups of arginine-containing amino acid sequences and synthetic polyarginine sequences are considered. The physiological characteristics of well-known arginine-containing peptides, such as RGD peptides, kyotorphin, and tuftsin, are described in detail. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2008, vol. 34, no. 2; see also http://www.maik.ru
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Pozzuolo S, Breme U, Salis B, Taylor G, Tonon G, Orsini G. Efficient bacterial expression of fusion proteins and their selective processing by a recombinant Kex-1 protease. Protein Expr Purif 2008; 59:334-41. [DOI: 10.1016/j.pep.2008.02.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2007] [Revised: 02/09/2008] [Accepted: 02/13/2008] [Indexed: 10/22/2022]
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