1
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Qin X, Ding R, Lu H, Zhang W, Wei S, Ji B, Geng R, Wu L, Chen Z. Identification of pivotal genes and regulatory networks associated with atherosclerotic carotid artery stenosis based on comprehensive bioinformatics analysis and machine learning. Front Pharmacol 2024; 15:1364160. [PMID: 38694921 PMCID: PMC11061441 DOI: 10.3389/fphar.2024.1364160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Accepted: 04/05/2024] [Indexed: 05/04/2024] Open
Abstract
Objective Bioinformatics methods were applied to investigate the pivotal genes and regulatory networks associated with atherosclerotic carotid artery stenosis (ACAS) and provide new insights for the treatment of this disease. Methods The study utilized five ACAS datasets (GSE100927, GSE11782, GESE28829, GSE41571, and GSE43292) downloaded from the NCBI GEO database. The first four datasets were combined as the training set (n = 99), while GSE43292 (n = 64) was used as the validation set. Difference analysis and functional enrichment analysis were then performed on the training set. The pathogenic targets of ACAS were screened by protein-protein interaction networks and MCODE analyses, combined with three machine learning algorithms. The results were next verified by analysis of inter-group differences and ROC curve analysis. Next, immune-related function and immune cell correlation analyses were performed, and plaques of human ACAS were applied to verify the results via immunohistochemistry (IH) and immunofluorescence (IF). Finally, the competing endogenous RNAs (ceRNA) and transcription factors (TFs) regulatory networks of the characterized genes were constructed. Results A total of 177 differentially expressed genes were identified, including 67 genes downregulated and 110 genes upregulated. Gene set enrichment analysis revealed that five pathways were active in the experimental group, including xenograft rejection, autoimmune thyroid disease, graft-versus-host disease, leishmaniasis infection, and lysosomes. Four key genes were identified, with C3AR1 being upregulated and FBLN5, PPP1R12A, and TPM1 being downregulated. The analysis of inter-group differences demonstrated that the four characterized genes were differentially expressed in both the control and experimental groups. The ROC analysis showed that they had high AUC values in both the training and validation sets. Therefore, a predictive ACAS patient nomogram model based on the screened genes was established. Correlation analysis revealed a positive correlation between C3AR1 expression and neutrophils, which was further validated in IH and IF. One or multiple lncRNAs may compete with the characterized genes for binding miRNAs. Additionally, each characterized gene interacts with multiple TFs. Conclusion Four pivotal genes were screened, and relevant ceRNA and TFs were predicted. These molecules may exert a crucial role in ACAS and serve as potential biomarkers and therapeutic targets.
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Affiliation(s)
- Xiaohong Qin
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
- Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Rui Ding
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Haoran Lu
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
- Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Wenfei Zhang
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Shanshan Wei
- Department of Oncology, Wuchang Hospital Affiliated to Wuhan University of Science and Technology, Wuhan, China
| | - Baowei Ji
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Rongxin Geng
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Liquan Wu
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Zhibiao Chen
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
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2
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Farrugia BL, Melrose J. The Glycosaminoglycan Side Chains and Modular Core Proteins of Heparan Sulphate Proteoglycans and the Varied Ways They Provide Tissue Protection by Regulating Physiological Processes and Cellular Behaviour. Int J Mol Sci 2023; 24:14101. [PMID: 37762403 PMCID: PMC10531531 DOI: 10.3390/ijms241814101] [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: 07/24/2023] [Revised: 09/03/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
This review examines the roles of HS-proteoglycans (HS-PGs) in general, and, in particular, perlecan and syndecan as representative examples and their interactive ligands, which regulate physiological processes and cellular behavior in health and disease. HS-PGs are essential for the functional properties of tissues both in development and in the extracellular matrix (ECM) remodeling that occurs in response to trauma or disease. HS-PGs interact with a biodiverse range of chemokines, chemokine receptors, protease inhibitors, and growth factors in immune regulation, inflammation, ECM stabilization, and tissue protection. Some cell regulatory proteoglycan receptors are dually modified hybrid HS/CS proteoglycans (betaglycan, CD47). Neurexins provide synaptic stabilization, plasticity, and specificity of interaction, promoting neurotransduction, neurogenesis, and differentiation. Ternary complexes of glypican-1 and Robbo-Slit neuroregulatory proteins direct axonogenesis and neural network formation. Specific neurexin-neuroligin complexes stabilize synaptic interactions and neural activity. Disruption in these interactions leads to neurological deficits in disorders of functional cognitive decline. Interactions with HS-PGs also promote or inhibit tumor development. Thus, HS-PGs have complex and diverse regulatory roles in the physiological processes that regulate cellular behavior and the functional properties of normal and pathological tissues. Specialized HS-PGs, such as the neurexins, pikachurin, and Eyes-shut, provide synaptic stabilization and specificity of neural transduction and also stabilize the axenome primary cilium of phototoreceptors and ribbon synapse interactions with bipolar neurons of retinal neural networks, which are essential in ocular vision. Pikachurin and Eyes-Shut interactions with an α-dystroglycan stabilize the photoreceptor synapse. Novel regulatory roles for HS-PGs controlling cell behavior and tissue function are expected to continue to be uncovered in this fascinating class of proteoglycan.
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Affiliation(s)
- Brooke L. Farrugia
- Department of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Melbourne, Melbourne, VIC 3010, Australia;
| | - James Melrose
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW 2052, Australia
- Raymond Purves Laboratory of Bone and Joint Research, Kolling Institute of Medical Research, Northern Sydney Local Health District, Royal North Shore Hospital, St. Leonards, NSW 2065, Australia
- Sydney Medical School (Northern), University of Sydney at Royal North Shore Hospital, St. Leonards, NSW 2065, Australia
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3
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Zhu Y, Cheung ALM. Proteoglycans and their functions in esophageal squamous cell carcinoma. World J Clin Oncol 2021; 12:507-521. [PMID: 34367925 PMCID: PMC8317653 DOI: 10.5306/wjco.v12.i7.507] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/13/2021] [Accepted: 06/02/2021] [Indexed: 02/06/2023] Open
Abstract
Esophageal squamous cell carcinoma (ESCC) is a highly malignant disease that has a poor prognosis. Its high lethality is mainly due to the lack of symptoms at early stages, which culminates in diagnosis at a late stage when the tumor has already metastasized. Unfortunately, the common cancer biomarkers have low sensitivity and specificity in esophageal cancer. Therefore, a better understanding of the molecular mechanisms underlying ESCC progression is needed to identify novel diagnostic markers and therapeutic targets for intervention. The invasion of cancer cells into the surrounding tissue is a crucial step for metastasis. During metastasis, tumor cells can interact with extracellular components and secrete proteolytic enzymes to remodel the surrounding tumor microenvironment. Proteoglycans are one of the major components of extracellular matrix. They are involved in multiple processes of cancer cell invasion and metastasis by interacting with soluble bioactive molecules, surrounding matrix, cell surface receptors, and enzymes. Apart from having diverse functions in tumor cells and their surrounding microenvironment, proteoglycans also have diagnostic and prognostic significance in cancer patients. However, the functional significance and underlying mechanisms of proteoglycans in ESCC are not well understood. This review summarizes the proteoglycans that have been studied in ESCC in order to provide a comprehensive view of the role of proteoglycans in the progression of this cancer type. A long term goal would be to exploit these molecules to provide new strategies for therapeutic intervention.
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Affiliation(s)
- Yun Zhu
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
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4
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Simeonovic CJ, Popp SK, Brown DJ, Li FJ, Lafferty ARA, Freeman C, Parish CR. Heparanase and Type 1 Diabetes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1221:607-630. [PMID: 32274728 DOI: 10.1007/978-3-030-34521-1_24] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Type 1 diabetes (T1D) results from autoimmune destruction of insulin-producing beta cells in pancreatic islets. The degradation of the glycosaminoglycan heparan sulfate (HS) by the endo-β-D-glycosidase heparanase plays a critical role in multiple stages of the disease process. Heparanase aids (i) migration of inflammatory leukocytes from the vasculature to the islets, (ii) intra-islet invasion by insulitis leukocytes, and (iii) selective destruction of beta cells. These disease stages are marked by the solubilization of HS in the subendothelial basement membrane (BM), HS breakdown in the peri-islet BM, and the degradation of HS inside beta cells, respectively. Significantly, healthy islet beta cells are enriched in highly sulfated HS which is essential for their viability, protection from damage by reactive oxygen species (ROS), beta cell function and differentiation. Consequently, mouse and human beta cells but not glucagon-producing alpha cells (which contain less-sulfated HS) are exquisitely vulnerable to heparanase-mediated damage. In vitro, the death of HS-depleted mouse and human beta cells can be prevented by HS replacement using highly sulfated HS mimetics or analogues. T1D progression in NOD mice and recent-onset T1D in humans correlate with increased expression of heparanase by circulating leukocytes of myeloid origin and heparanase-expressing insulitis leukocytes. Treatment of NOD mice with the heparanase inhibitor and HS replacer, PI-88, significantly reduced T1D incidence by 50%, impaired the development of insulitis and preserved beta cell HS. These outcomes identified heparanase as a novel destructive tool in T1D, distinct from the conventional cytotoxic and apoptosis-inducing mechanisms of autoreactive T cells. In contrast to exogenous catalytically active heparanase, endogenous heparanase may function in HS homeostasis, gene expression and insulin secretion in normal beta cells and immune gene expression in leukocytes. In established diabetes, the interplay between hyperglycemia, local inflammatory cells (e.g. macrophages) and heparanase contributes to secondary micro- and macro-vascular disease. We have identified dual activity heparanase inhibitors/HS replacers as a novel class of therapeutic for preventing T1D progression and potentially for mitigating secondary vascular disease that develops with long-term T1D.
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Affiliation(s)
- Charmaine J Simeonovic
- Department of Immunology and Infectious Disease, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia.
| | - Sarah K Popp
- Department of Immunology and Infectious Disease, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Debra J Brown
- Department of Immunology and Infectious Disease, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Fei-Ju Li
- Department of Immunology and Infectious Disease, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Antony R A Lafferty
- Department of Paediatrics, The Canberra Hospital, Woden, ACT, Australia.,The ANU Medical School, The Australian National University, Canberra, ACT, Australia
| | - Craig Freeman
- ACRF Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Christopher R Parish
- ACRF Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
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5
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Hellman LT, Akula S, Thorpe M, Fu Z. Tracing the Origins of IgE, Mast Cells, and Allergies by Studies of Wild Animals. Front Immunol 2017; 8:1749. [PMID: 29312297 PMCID: PMC5742104 DOI: 10.3389/fimmu.2017.01749] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 11/24/2017] [Indexed: 12/23/2022] Open
Abstract
In most industrialized countries, allergies have increased in frequency quite dramatically during the past 50 years. Estimates show that 20–30% of the populations are affected. Allergies have thereby become one of the major medical challenges of the twenty-first century. Despite several theories including the hygiene hypothesis, there are still very few solid clues concerning the causes of this increase. To trace the origins of allergies, we have studied cells and molecules of importance for the development of IgE-mediated allergies, including the repertoire of immunoglobulin genes. These studies have shown that IgE and IgG most likely appeared by a gene duplication of IgY in an early mammal, possibly 220–300 million years ago. Receptors specific for IgE and IgG subsequently appeared in parallel with the increase in Ig isotypes from a subfamily of the recently identified Fc receptor-like molecules. Circulating IgE levels are generally very low in humans and laboratory rodents. However, when dogs and Scandinavian wolfs were analyzed, IgE levels were found to be 100–200 times higher compared to humans, indicating a generally much more active IgE synthesis in free-living animals, most likely connected to intestinal parasite infections. One of the major effector molecules released upon IgE-mediated activation by mast cells are serine proteases. These proteases, which belong to the large family of hematopoietic serine proteases, are extremely abundant and can account for up to 35% of the total cellular protein. Recent studies show that several of these enzymes, including the chymases and tryptases, are old. Ancestors for these enzymes were most likely present in an early mammal more than 200 million years ago before the separation of the three extant mammalian lineages; monotremes, marsupials, and placental mammals. The aim is now to continue these studies of mast cell biology and IgE to obtain additional clues to their evolutionary conserved functions. A focus concerns why the humoral immune response involving IgE and mast cells have become so dysregulated in humans as well as several of our domestic companion animals.
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Affiliation(s)
- Lars Torkel Hellman
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Srinivas Akula
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Michael Thorpe
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Zhirong Fu
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
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6
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Abstract
Comparative protein structure modeling predicts the three-dimensional structure of a given protein sequence (target) based primarily on its alignment to one or more proteins of known structure (templates). The prediction process consists of fold assignment, target-template alignment, model building, and model evaluation. This unit describes how to calculate comparative models using the program MODELLER and how to use the ModBase database of such models, and discusses all four steps of comparative modeling, frequently observed errors, and some applications. Modeling lactate dehydrogenase from Trichomonas vaginalis (TvLDH) is described as an example. The download and installation of the MODELLER software is also described. © 2016 by John Wiley & Sons, Inc.
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Affiliation(s)
- Benjamin Webb
- University of California at San Francisco, San Francisco, California
| | - Andrej Sali
- University of California at San Francisco, San Francisco, California
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7
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Webb B, Sali A. Comparative Protein Structure Modeling Using MODELLER. CURRENT PROTOCOLS IN BIOINFORMATICS 2016; 54:5.6.1-5.6.37. [PMID: 27322406 PMCID: PMC5031415 DOI: 10.1002/cpbi.3] [Citation(s) in RCA: 1856] [Impact Index Per Article: 232.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Comparative protein structure modeling predicts the three-dimensional structure of a given protein sequence (target) based primarily on its alignment to one or more proteins of known structure (templates). The prediction process consists of fold assignment, target-template alignment, model building, and model evaluation. This unit describes how to calculate comparative models using the program MODELLER and how to use the ModBase database of such models, and discusses all four steps of comparative modeling, frequently observed errors, and some applications. Modeling lactate dehydrogenase from Trichomonas vaginalis (TvLDH) is described as an example. The download and installation of the MODELLER software is also described. © 2016 by John Wiley & Sons, Inc.
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Affiliation(s)
- Benjamin Webb
- University of California at San Francisco, San Francisco, California
| | - Andrej Sali
- University of California at San Francisco, San Francisco, California
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8
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Nguyen K, Rabenstein DL. Interaction of the Heparin-Binding Consensus Sequence of β-Amyloid Peptides with Heparin and Heparin-Derived Oligosaccharides. J Phys Chem B 2016; 120:2187-97. [PMID: 26872053 DOI: 10.1021/acs.jpcb.5b12235] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Alzheimer's disease (AD) is characterized by the presence of amyloid plaques in the AD brain. Comprised primarily of the 40- and 42-residue β-amyloid (Aβ) peptides, there is evidence that the heparan sulfate (HS) of heparan sulfate proteoglycans (HSPGs) plays a role in amyloid plaque formation and stability; however, details of the interaction of Aβ peptides with HS are not known. We have characterized the interaction of heparin and heparin-derived oligosaccharides with a model peptide for the heparin- and HS-binding domain of Aβ peptides (Ac-VHHQKLV-NH2; Aβ(12-18)), with mutants of Aβ(12-18), and with additional histidine-containing peptides. The nature of the binding interaction was characterized by NMR, binding constants and other thermodynamic parameters were determined by isothermal titration calorimetry (ITC), and relative binding affinities were determined by heparin affinity chromatography. The binding of Aβ(12-18) by heparin and heparin-derived oligosaccharides is pH-dependent, with the imidazolium groups of the histidine side chains interacting site-specifically within a cleft created by a trisaccharide sequence of heparin, the binding is mediated by electrostatic interactions, and there is a significant entropic contribution to the binding free energy as a result of displacement of Na(+) ions from heparin upon binding of cationic Aβ(12-18). The binding constant decreases as the size of the heparin-derived oligosaccharide decreases and as the concentration of Na(+) ion in the bulk solution increases. Structure-binding relationships characterized in this study are analyzed and discussed in terms of the counterion condensation theory of the binding of cationic peptides by anionic polyelectrolytes.
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Affiliation(s)
- Khanh Nguyen
- Department of Chemistry University of California, Riverside , Riverside, California 92521, United States
| | - Dallas L Rabenstein
- Department of Chemistry University of California, Riverside , Riverside, California 92521, United States
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9
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Sutton VR, Brennan AJ, Ellis S, Danne J, Thia K, Jenkins MR, Voskoboinik I, Pejler G, Johnstone RW, Andrews DM, Trapani JA. Serglycin determines secretory granule repertoire and regulates natural killer cell and cytotoxic T lymphocyte cytotoxicity. FEBS J 2016; 283:947-61. [PMID: 26756195 DOI: 10.1111/febs.13649] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 12/31/2015] [Accepted: 01/08/2015] [Indexed: 12/28/2022]
Abstract
The anionic proteoglycan serglycin is a major constituent of secretory granules in cytotoxic T lymphocyte (CTL)/natural killer (NK) cells, and is proposed to promote the safe storage of the mostly cationic granule toxins, granzymes and perforin. Despite the extensive defects of mast cell function reported in serglycin gene-disrupted mice, no comprehensive study of physiologically relevant CTL/NK cell populations has been reported. We show that the cytotoxicity of serglycin-deficient CTL and NK cells is severely compromised but can be partly compensated in both cell types when they become activated. Reduced intracellular granzyme B levels were noted, particularly in CD27(+) CD11b(+) mature NK cells, whereas serglycin(-/-) TCR-transgenic (OTI) CD8 T cells also had reduced perforin stores. Culture supernatants from serglycin(-/-) OTI T cells and interleukin-2-activated NK contained increased granzyme B, linking reduced storage with heightened export. By contrast, granzyme A was not significantly reduced in cells lacking serglycin, indicating differentially regulated trafficking and/or storage for the two granzymes. A quantitative analysis of different granule classes by transmission electronmicroscopy showed a selective loss of dense-core granules in serglycin(-/-) CD8(+) CTLs, although other granule types were maintained quantitatively. The findings of the present study show that serglycin plays a critical role in the maturation of dense-core cytotoxic granules in cytotoxic lymphocytes and the trafficking and storage of perforin and granzyme B, whereas granzyme A is unaffected. The skewed retention of cytotoxic effector molecules markedly reduces CTL/NK cell cytotoxicity, although this is partly compensated for as a result of activating the cells by physiological means.
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Affiliation(s)
- Vivien R Sutton
- Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Amelia J Brennan
- Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Sarah Ellis
- Microscopy and Histology, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Jill Danne
- Microscopy and Histology, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Kevin Thia
- Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Misty R Jenkins
- Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Ilia Voskoboinik
- Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Gunnar Pejler
- Department of Medical Biochemistry and Microbiology, Uppsala University, Sweden.,Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ricky W Johnstone
- Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.,The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Victoria, Australia
| | - Daniel M Andrews
- Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Joseph A Trapani
- Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.,The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Victoria, Australia
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10
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Farrugia BL, Whitelock JM, O'Grady R, Caterson B, Lord MS. Mast Cells Produce a Unique Chondroitin Sulfate Epitope. J Histochem Cytochem 2015; 64:85-98. [PMID: 26586669 DOI: 10.1369/0022155415620649] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 11/11/2015] [Indexed: 01/01/2023] Open
Abstract
The granules of mast cells contain a myriad of mediators that are stored and protected by the sulfated glycosaminoglycan (GAG) chains that decorate proteoglycans. Whereas heparin is the GAG predominantly associated with mast cells, mast cell proteoglycans are also decorated with heparan sulfate and chondroitin sulfate (CS). This study investigated a unique CS structure produced by mast cells that was detected with the antibody clone 2B6 in the absence of chondroitinase ABC digestion. Mast cells in rodent tissue sections were characterized using toluidine blue, Leder stain and the presence of mast cell tryptase. The novel CS epitope was identified in rodent tissue sections and localized to cells that were morphologically similar to cells chemically identified as mast cells. The rodent mast cell-like line RBL-2H3 was also shown to express the novel CS epitope. This epitope co-localized with multiple CS proteoglycans in both rodent tissue and RBL-2H3 cultured cells. These findings suggest that the novel CS epitope that decorates mast cell proteoglycans may play a role in the way these chains are structured in mast cells.
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Affiliation(s)
- Brooke L Farrugia
- Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, NSW, Australia (BLF, JMW, ROG, MSL)
| | - John M Whitelock
- Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, NSW, Australia (BLF, JMW, ROG, MSL)
| | - Robert O'Grady
- Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, NSW, Australia (BLF, JMW, ROG, MSL)
| | - Bruce Caterson
- Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom (BC)
| | - Megan S Lord
- Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, NSW, Australia (BLF, JMW, ROG, MSL)
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11
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Abstract
Functional characterization of a protein sequence is one of the most frequent problems in biology. This task is usually facilitated by accurate three-dimensional (3-D) structure of the studied protein. In the absence of an experimentally determined structure, comparative or homology modeling can sometimes provide a useful 3-D model for a protein that is related to at least one known protein structure. Comparative modeling predicts the 3-D structure of a given protein sequence (target) based primarily on its alignment to one or more proteins of known structure (templates). The prediction process consists of fold assignment, target-template alignment, model building, and model evaluation. This unit describes how to calculate comparative models using the program MODELLER and discusses all four steps of comparative modeling, frequently observed errors, and some applications. Modeling lactate dehydrogenase from Trichomonas vaginalis (TvLDH) is described as an example. The download and installation of the MODELLER software is also described.
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Affiliation(s)
- Benjamin Webb
- University of California at San Francisco, San Francisco, California
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12
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Prieto-García A, Castells MC, Hansbro PM, Stevens RL. Mast cell-restricted tetramer-forming tryptases and their beneficial roles in hemostasis and blood coagulation. Immunol Allergy Clin North Am 2014; 34:263-81. [PMID: 24745673 DOI: 10.1016/j.iac.2014.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Tetramer-forming tryptase (hTryptase-β) was recently discovered to have a prominent role in preventing the internal accumulation of life-threatening fibrin deposits and fibrin-platelet clots. The anticoagulant activity of hTryptase-β is an explanation for the presence of hemorrhagic disorders in some patients with anaphylaxis or mastocytosis. The fragments of hFibrinogen formed by the proteolysis of this prominent protein by hTryptase-β could be used as biomarkers in the blood and/or urine for the identification and monitoring of patients with mast cell-dependent disorders. Recombinant hTryptase-β has potential to be used in clinical settings where it is desirable to inhibit blood coagulation.
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Affiliation(s)
- Alicia Prieto-García
- Allergy Service, Hospital Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Dr Esquerdo 46, Madrid 28007, Spain.
| | - Mariana C Castells
- Division of Rheumatology, Immunology, and Allergy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 1 Jimmy Fund Way, Smith Building, Boston, MA 02115, USA
| | - Philip M Hansbro
- Priority Research Centre for Asthma and Respiratory Disease, Hunter Medical Research Institute and University of Newcastle, 1 Kookaburra Circuit, Newcastle, NSW 2300, Australia
| | - Richard L Stevens
- Division of Rheumatology, Immunology, and Allergy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 1 Jimmy Fund Way, Smith Building, Boston, MA 02115, USA
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13
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Abstract
Structural proteomics aims to understand the structural basis of protein interactions and functions. A prerequisite for this is the availability of 3D protein structures that mediate the biochemical interactions. The explosion in the number of available gene sequences set the stage for the next step in genome-scale projects -- to obtain 3D structures for each protein. To achieve this ambitious goal, the slow and costly structure determination experiments are supplemented with theoretical approaches. The current state and recent advances in structure modeling approaches are reviewed here, with special emphasis on comparative protein structure modeling techniques.
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Affiliation(s)
- András Fiser
- Department of Biochemistry, Seaver Foundation Center for Bioinformatics, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, USA.
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14
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Cashman DJ, Ortega DR, Zhulin IB, Baudry J. Homology modeling of the CheW coupling protein of the chemotaxis signaling complex. PLoS One 2013; 8:e70705. [PMID: 23950985 PMCID: PMC3737408 DOI: 10.1371/journal.pone.0070705] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 06/21/2013] [Indexed: 11/23/2022] Open
Abstract
Homology models of the E. coli and T. maritima chemotaxis protein CheW were constructed to assess the quality of structural predictions and their applicability in chemotaxis research: i) a model of E. coli CheW was constructed using the T. maritima CheW NMR structure as a template, and ii) a model of T. maritima CheW was constructed using the E. coli CheW NMR structure as a template. The conformational space accessible to the homology models and to the NMR structures was investigated using molecular dynamics and Monte Carlo simulations. The results show that even though static homology models of CheW may be partially structurally different from their corresponding experimentally determined structures, the conformational space they can access through their dynamic variations can be similar, for specific regions of the protein, to that of the experimental NMR structures. When CheW homology models are allowed to explore their local accessible conformational space, modeling can provide a rational path to predicting CheW interactions with the MCP and CheA proteins of the chemotaxis complex. Homology models of CheW (and potentially, of other chemotaxis proteins) should be seen as snapshots of an otherwise larger ensemble of accessible conformational space.
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Affiliation(s)
- Derek J. Cashman
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, United States of America
- UT/ORNL Center for Molecular Biophysics, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Davi R. Ortega
- Department of Physics, University of Tennessee, Knoxville, Tennessee, United States of America
- Joint Institute for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Igor B. Zhulin
- Joint Institute for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Jerome Baudry
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, United States of America
- UT/ORNL Center for Molecular Biophysics, University of Tennessee, Knoxville, Tennessee, United States of America
- * E-mail:
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15
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Jung M, Lord MS, Cheng B, Lyons JG, Alkhouri H, Hughes JM, McCarthy SJ, Iozzo RV, Whitelock JM. Mast cells produce novel shorter forms of perlecan that contain functional endorepellin: a role in angiogenesis and wound healing. J Biol Chem 2012; 288:3289-304. [PMID: 23235151 DOI: 10.1074/jbc.m112.387811] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mast cells are derived from hematopoietic progenitors that are known to migrate to and reside within connective and mucosal tissues, where they differentiate and respond to various stimuli by releasing pro-inflammatory mediators, including histamine, growth factors, and proteases. This study demonstrated that primary human mast cells as well as the rat and human mast cell lines, RBL-2H3 and HMC-1, produce the heparan sulfate proteoglycan, perlecan, with a molecular mass of 640 kDa as well as smaller molecular mass species of 300 and 130 kDa. Utilizing domain-specific antibodies coupled with N-terminal sequencing, it was confirmed that both forms contained the C-terminal module of the protein core known as endorepellin, which were generated by mast cell-derived proteases. Domain-specific RT-PCR experiments demonstrated that transcripts corresponding to domains I and V, including endorepellin, were present; however, mRNA transcripts corresponding to regions of domain III were not present, suggesting that these cells were capable of producing spliced forms of the protein core. Fractions from mast cell cultures that were enriched for these fragments were shown to bind endothelial cells via the α(2)β(1) integrin and stimulate the migration of cells in "scratch assays," both activities of which were inhibited by incubation with either anti-endorepellin or anti-perlecan antibodies. This study shows for the first time that mast cells secrete and process the extracellular proteoglycan perlecan into fragments containing the endorepellin C-terminal region that regulate angiogenesis and matrix turnover, which are both key events in wound healing.
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Affiliation(s)
- Moonsun Jung
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
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16
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Abstract
Serglycin belongs to a family of small proteoglycans with Ser-Gly dipeptide repeats, and it is modified with different types of glycosaminoglycan side chains. Intracellular serglycin affects the retention and secretion of proteases, chemokines, or other cytokines by physically binding to these factors in secretory granules. Extracellular serglycin has been found to be released by several types of human cancer cells, and it is able to promote the metastasis of nasopharyngeal carcinoma cells. Serglycin can bind to CD44, which is another glycoprotein located in cellular membrane. Serglycin's function of promoting cancer cell metastasis depends on glycosylation of its core protein, which can be achieved by autocrine as well as paracrine secretion mechanisms. Further investigations are warranted to elucidate serglycin signaling mechanisms with the goal of targeting them to prevent cancer cell metastasis.
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Affiliation(s)
- Xin-Jian Li
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P. R. China. qianchn@ sysucc.org.cn
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17
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Borta H, Aroso M, Rinn C, Gomez-Lazaro M, Vitorino R, Zeuschner D, Grabenbauer M, Amado F, Schrader M. Analysis of low abundance membrane-associated proteins from rat pancreatic zymogen granules. J Proteome Res 2010; 9:4927-39. [PMID: 20707389 DOI: 10.1021/pr100052q] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Zymogen granules (ZG) are specialized storage organelles in the exocrine pancreas that allow the sorting, packaging, and regulated apical secretion of digestive enzymes. As there is a critical need for further understanding of the key processes in regulated secretion to develop new therapeutic options in medicine, we applied a suborganellar proteomics approach to identify peripheral membrane-associated ZG proteins. We focused on the analysis of a "basic" group (pH range 6.2-11) with about 46 spots among which 44 were identified by tandem mass spectrometry. These spots corresponded to 16 unique proteins, including rat mast cell chymase (RMCP-1) and peptidyl-prolyl cis-trans isomerase B (PpiB; cyclophilin B), an ER-resident protein. To confirm that these proteins were specific to zymogen granules and not contaminants of the preparation, we conducted a series of validation experiments. Immunoblotting of ZG subfractions revealed that chymase and PpiB behaved like bona fide peripheral membrane proteins. Their expression in rat pancreas was regulated by feeding behavior. Ultrastructural and immunofluorescence studies confirmed their ZG localization. Furthermore, a chymase-YFP fusion protein was properly targeted to ZG in pancreatic AR42J cells. Interestingly, for both proteins, proteoglycan-binding properties have been reported. The importance of our findings for sorting and packaging during ZG formation is discussed.
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Affiliation(s)
- Heike Borta
- Department of Cell Biology and Cell Pathology, Philipps University of Marburg, Robert Koch Strasse 6, Marburg, Germany
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18
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Schick BP. Serglycin proteoglycan deletion in mouse platelets: physiological effects and their implications for platelet contributions to thrombosis, inflammation, atherosclerosis, and metastasis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2010; 93:235-87. [PMID: 20807648 DOI: 10.1016/s1877-1173(10)93011-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Serglycin is found in all nucleated hematopoietic cells and platelets, blood vessels, various reproductive and developmental tissues, and in chondrocytes. The serglycin knockout mouse has demonstrated that this proteoglycan is required for proper generation and function of secretory granules in several hematopoietic cells. The effects on platelets are profound, and include diminishing platelet aggregation responses and formation of platelet thrombi. This chapter will review cell-specific aspects of serglycin structure, its gene regulation, cell and tissue localization, and the effects of serglycin deletion on hematopoietic cell granule structure and function. The effects of serglycin knockout on platelets are described and discussed in detail. Rationales for further investigations into the contribution of serglycin to the known roles of platelets in thrombosis, inflammation, atherosclerosis, and tumor metastasis are presented.
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Affiliation(s)
- Barbara P Schick
- Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA, USA
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19
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Kim S, Carrillo M, Kulkarni V, Jagadeeswaran P. Evolution of primary hemostasis in early vertebrates. PLoS One 2009; 4:e8403. [PMID: 20037653 PMCID: PMC2793433 DOI: 10.1371/journal.pone.0008403] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 11/18/2009] [Indexed: 11/17/2022] Open
Abstract
Hemostasis is a defense mechanism which protects the organism in the event of injury to stop bleeding. Recently, we established that all the known major mammalian hemostatic factors are conserved in early vertebrates. However, since their highly vascularized gills experience high blood pressure and are exposed to the environment, even very small injuries could be fatal to fish. Since trypsins are forerunners for coagulation proteases and are expressed by many extrapancreatic cells such as endothelial cells and epithelial cells, we hypothesized that trypsin or trypsin-like proteases from gill epithelial cells may protect these animals from gill bleeding following injuries. In this paper we identified the release of three different trypsins from fish gills into water under stress or injury, which have tenfold greater serine protease activity compared to bovine trypsin. We found that these trypsins activate the thrombocytes and protect the fish from gill bleeding. We found 27 protease-activated receptors (PARs) by analyzing zebrafish genome and classified them into five groups, based on tethering peptides, and two families, PAR1 and PAR2, based on homologies. We also found a canonical member of PAR2 family, PAR2-21A which is activated more readily by trypsin, and PAR2-21A tethering peptide stops gill bleeding just as trypsin. This finding provides evidence that trypsin cleaves a PAR2 member on thrombocyte surface. In conclusion, we believe that the gills are evolutionarily selected to produce trypsin to activate PAR2 on thrombocyte surface and protect the gills from bleeding. We also speculate that trypsin may also protect the fish from bleeding from other body injuries due to quick contact with the thrombocytes. Thus, this finding provides evidence for the role of trypsins in primary hemostasis in early vertebrates.
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Affiliation(s)
- Seongcheol Kim
- Department of Biological Sciences, University of North Texas, Denton, Texas, USA
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20
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D’Abramo M, Meyer T, Bernadó P, Pons C, Recio JF, Orozco M. On the Use of low-resolution Data to Improve Structure Prediction of Proteins and Protein Complexes. J Chem Theory Comput 2009; 5:3129-37. [DOI: 10.1021/ct900305m] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Marco D’Abramo
- Molecular Modeling and Bioinformatics Unit, IRB-BSC Joint Research Program in Computational Biology, Institute for Research in Biomedicine Josep Samitier 1-5, Barcelona 08028, Spain and Barcelona Supercomputing Center, Jordi Girona 29, Barcelona 08034, Spain, Structural and Computational Biology Program, Institute for Research in Biomedicine Josep Samitier 1-5, Barcelona 08028, Spain, Life Sciences Department, Barcelona Supercomputing Center, Jordi Girona 29, Barcelona 08034, Spain, Departament de
| | - Tim Meyer
- Molecular Modeling and Bioinformatics Unit, IRB-BSC Joint Research Program in Computational Biology, Institute for Research in Biomedicine Josep Samitier 1-5, Barcelona 08028, Spain and Barcelona Supercomputing Center, Jordi Girona 29, Barcelona 08034, Spain, Structural and Computational Biology Program, Institute for Research in Biomedicine Josep Samitier 1-5, Barcelona 08028, Spain, Life Sciences Department, Barcelona Supercomputing Center, Jordi Girona 29, Barcelona 08034, Spain, Departament de
| | - Pau Bernadó
- Molecular Modeling and Bioinformatics Unit, IRB-BSC Joint Research Program in Computational Biology, Institute for Research in Biomedicine Josep Samitier 1-5, Barcelona 08028, Spain and Barcelona Supercomputing Center, Jordi Girona 29, Barcelona 08034, Spain, Structural and Computational Biology Program, Institute for Research in Biomedicine Josep Samitier 1-5, Barcelona 08028, Spain, Life Sciences Department, Barcelona Supercomputing Center, Jordi Girona 29, Barcelona 08034, Spain, Departament de
| | - Carles Pons
- Molecular Modeling and Bioinformatics Unit, IRB-BSC Joint Research Program in Computational Biology, Institute for Research in Biomedicine Josep Samitier 1-5, Barcelona 08028, Spain and Barcelona Supercomputing Center, Jordi Girona 29, Barcelona 08034, Spain, Structural and Computational Biology Program, Institute for Research in Biomedicine Josep Samitier 1-5, Barcelona 08028, Spain, Life Sciences Department, Barcelona Supercomputing Center, Jordi Girona 29, Barcelona 08034, Spain, Departament de
| | - Juan Fernández Recio
- Molecular Modeling and Bioinformatics Unit, IRB-BSC Joint Research Program in Computational Biology, Institute for Research in Biomedicine Josep Samitier 1-5, Barcelona 08028, Spain and Barcelona Supercomputing Center, Jordi Girona 29, Barcelona 08034, Spain, Structural and Computational Biology Program, Institute for Research in Biomedicine Josep Samitier 1-5, Barcelona 08028, Spain, Life Sciences Department, Barcelona Supercomputing Center, Jordi Girona 29, Barcelona 08034, Spain, Departament de
| | - Modesto Orozco
- Molecular Modeling and Bioinformatics Unit, IRB-BSC Joint Research Program in Computational Biology, Institute for Research in Biomedicine Josep Samitier 1-5, Barcelona 08028, Spain and Barcelona Supercomputing Center, Jordi Girona 29, Barcelona 08034, Spain, Structural and Computational Biology Program, Institute for Research in Biomedicine Josep Samitier 1-5, Barcelona 08028, Spain, Life Sciences Department, Barcelona Supercomputing Center, Jordi Girona 29, Barcelona 08034, Spain, Departament de
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21
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Rao KN, Brown MA. Mast cells: multifaceted immune cells with diverse roles in health and disease. Ann N Y Acad Sci 2009; 1143:83-104. [PMID: 19076346 DOI: 10.1196/annals.1443.023] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mast cells were discovered more than 100 years ago and until recently, have been considered renegades of the host with the sole purpose of perpetuating allergy. The discovery of mast cell-deficient mice that could be reconstituted with mast cells (the so called "mast cell knock-in" mice) has allowed the study of the in vivo functions of mast cells and revealed several new facets of these cells. It is now evident that mast cells have a much broader impact on many physiological and pathologic processes. Mast cells, particularly through their dynamic interaction with the nervous system, have been implicated in wound healing, tissue remodeling, and homeostasis. Perhaps the most progress has been made in our understanding of the role of mast cells in immunity outside the realm of allergy, and host defense. Mast cells play critical roles in both innate and adaptive immunity, including immune tolerance. Greater insight into mast cell biology has prompted studies probing the additional consequences of mast cell dysfunction, which reveal a central role for mast cells in the pathogenesis of autoimmune disorders, cardiovascular disorders, and cancer. Here, we review recent developments in the study of mast cells, which present a complex picture of mast cell functions.
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Affiliation(s)
- Kavitha N Rao
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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22
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Gandhi NS, Mancera RL. The Structure of Glycosaminoglycans and their Interactions with Proteins. Chem Biol Drug Des 2008; 72:455-82. [DOI: 10.1111/j.1747-0285.2008.00741.x] [Citation(s) in RCA: 703] [Impact Index Per Article: 43.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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23
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Eswar N, Webb B, Marti-Renom MA, Madhusudhan MS, Eramian D, Shen MY, Pieper U, Sali A. Comparative protein structure modeling using MODELLER. ACTA ACUST UNITED AC 2008; Chapter 2:Unit 2.9. [PMID: 18429317 DOI: 10.1002/0471140864.ps0209s50] [Citation(s) in RCA: 750] [Impact Index Per Article: 46.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Functional characterization of a protein sequence is a common goal in biology, and is usually facilitated by having an accurate three-dimensional (3-D) structure of the studied protein. In the absence of an experimentally determined structure, comparative or homology modeling can sometimes provide a useful 3-D model for a protein that is related to at least one known protein structure. Comparative modeling predicts the 3-D structure of a given protein sequence (target) based primarily on its alignment to one or more proteins of known structure (templates). The prediction process consists of fold assignment, target-template alignment, model building, and model evaluation. This unit describes how to calculate comparative models using the program MODELLER and discusses all four steps of comparative modeling, frequently observed errors, and some applications. Modeling lactate dehydrogenase from Trichomonas vaginalis (TvLDH) is described as an example. The download and installation of the MODELLER software is also described.
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Affiliation(s)
- Narayanan Eswar
- University of California at San Francisco, San Francisco, California, USA
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24
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Eswar N, Webb B, Marti-Renom MA, Madhusudhan MS, Eramian D, Shen MY, Pieper U, Sali A. Comparative protein structure modeling using Modeller. ACTA ACUST UNITED AC 2008; Chapter 5:Unit-5.6. [PMID: 18428767 DOI: 10.1002/0471250953.bi0506s15] [Citation(s) in RCA: 1766] [Impact Index Per Article: 110.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Functional characterization of a protein sequence is one of the most frequent problems in biology. This task is usually facilitated by accurate three-dimensional (3-D) structure of the studied protein. In the absence of an experimentally determined structure, comparative or homology modeling can sometimes provide a useful 3-D model for a protein that is related to at least one known protein structure. Comparative modeling predicts the 3-D structure of a given protein sequence (target) based primarily on its alignment to one or more proteins of known structure (templates). The prediction process consists of fold assignment, target-template alignment, model building, and model evaluation. This unit describes how to calculate comparative models using the program MODELLER and discusses all four steps of comparative modeling, frequently observed errors, and some applications. Modeling lactate dehydrogenase from Trichomonas vaginalis (TvLDH) is described as an example. The download and installation of the MODELLER software is also described.
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Affiliation(s)
- Narayanan Eswar
- University of California at San Francisco San Francisco, California
| | - Ben Webb
- University of California at San Francisco San Francisco, California
| | | | - M S Madhusudhan
- University of California at San Francisco San Francisco, California
| | - David Eramian
- University of California at San Francisco San Francisco, California
| | - Min-Yi Shen
- University of California at San Francisco San Francisco, California
| | - Ursula Pieper
- University of California at San Francisco San Francisco, California
| | - Andrej Sali
- University of California at San Francisco San Francisco, California
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25
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Trivedi NN, Raymond WW, Caughey GH. Chimerism, point mutation, and truncation dramatically transformed mast cell δ-tryptases during primate evolution. J Allergy Clin Immunol 2008; 121:1262-8. [DOI: 10.1016/j.jaci.2008.01.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Revised: 01/03/2008] [Accepted: 01/16/2008] [Indexed: 11/24/2022]
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26
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Gandhi NS, Coombe DR, Mancera RL. Platelet Endothelial Cell Adhesion Molecule 1 (PECAM-1) and Its Interactions with Glycosaminoglycans: 1. Molecular Modeling Studies. Biochemistry 2008; 47:4851-62. [DOI: 10.1021/bi702455e] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Neha S. Gandhi
- Western Australian Biomedical Research Institute, and Schools of Pharmacy and Biomedical Sciences, Curtin University of Technology, GPO Box U1987, Perth, Western Australia 6845, Australia
| | - Deirdre R. Coombe
- Western Australian Biomedical Research Institute, and Schools of Pharmacy and Biomedical Sciences, Curtin University of Technology, GPO Box U1987, Perth, Western Australia 6845, Australia
| | - Ricardo L. Mancera
- Western Australian Biomedical Research Institute, and Schools of Pharmacy and Biomedical Sciences, Curtin University of Technology, GPO Box U1987, Perth, Western Australia 6845, Australia
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27
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Stevens RL, Adachi R. Protease-proteoglycan complexes of mouse and human mast cells and importance of their beta-tryptase-heparin complexes in inflammation and innate immunity. Immunol Rev 2007; 217:155-67. [PMID: 17498058 DOI: 10.1111/j.1600-065x.2007.00525.x] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Approximately 50% of the weight of a mature mast cell (MC) consists of varied neutral proteases stored in the cell's secretory granules ionically bound to serglycin proteoglycans that contain heparin and/or chondroitin sulfate E/diB chains. Mouse MCs express the exopeptidase carboxypeptidase A3 and at least 15 serine proteases [designated as mouse MC protease (mMCP) 1-11, transmembrane tryptase/tryptase gamma/protease serine member S (Prss) 31, cathepsin G, granzyme B, and neuropsin/Prss19]. mMCP-6, mMCP-7, mMCP-11/Prss34, and Prss31 are the four members of the chromosome 17A3.3 family of tryptases that are preferentially expressed in MCs. One of the challenges ahead is to understand why MCs express so many different protease-proteoglycan macromolecular complexes. MC-like cells that contain tryptase-heparin complexes in their secretory granules have been identified in the Ciona intestinalis and Styela plicata urochordates that appeared approximately 500 million years ago. Because sea squirts lack B cells and T cells, it is likely that MCs and their tryptase-proteoglycan granule mediators initially appeared in lower organisms as part of their innate immune system. The conservation of MCs throughout evolution suggests that some of these protease-proteoglycan complexes are essential to our survival. In support of this conclusion, no human has been identified that lacks MCs. Moreover, transgenic mice lacking the beta-tryptase mMCP-6 are unable to combat a Klebsiella pneumoniae infection effectively. Here we summarize the nature and function of some of the tryptase-serglycin proteoglycan complexes found in mouse and human MCs.
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Affiliation(s)
- Richard L Stevens
- Department of Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, USA.
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28
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McNeil HP, Adachi R, Stevens RL. Mast cell-restricted tryptases: structure and function in inflammation and pathogen defense. J Biol Chem 2007; 282:20785-9. [PMID: 17504754 DOI: 10.1074/jbc.r700017200] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mast cells (MCs) are highly specialized immune cells present in mammals and in lower organisms that predate the development of adaptive immunity. The strong evolutionary pressure to retain MCs for >500 million years suggests critical roles for these cells in our survival. In support of this conclusion, no human has been identified to date that lacks MCs, despite the adverse roles of MCs in systemic anaphylaxis and varied inflammatory disorders. MCs express numerous lineage-restricted neutral proteases, and four members of the chromosome 17A3.3 family of tryptases are preferentially expressed in mouse MCs. The anatomical location of MCs at host-environment interfaces has raised the possibility that some of these enzymes are evolutionally conserved because they are needed for combating infectious organisms. Here we review recent insights into the structure and function of MC tryptases in inflammation and host defense against bacteria and other infectious organisms.
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Affiliation(s)
- H Patrick McNeil
- Department of Rheumatology, Liverpool Hospital and South Western Sydney Clinical School, University of New South Wales, Sydney, Australia, 2052.
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29
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Abstract
Mast cells (MCs) are traditionally thought of as a nuisance for its host, for example, by causing many of the symptoms associated with allergic reactions. In addition, recent research has put focus on MCs for displaying harmful effects during various autoimmune disorders. On the other hand, MCs can also be beneficial for its host, for example, by contributing to the defense against insults such as bacteria, parasites, and snake venom toxins. When the MC is challenged by an external stimulus, it may respond by degranulation. In this process, a number of powerful preformed inflammatory "mediators" are released, including cytokines, histamine, serglycin proteoglycans, and several MC-specific proteases: chymases, tryptases, and carboxypeptidase A. Although the exact effector mechanism(s) by which MCs carry out their either beneficial or harmful effects in vivo are in large parts unknown, it is reasonable to assume that these mediators may contribute in profound ways. Among the various MC mediators, the exact biological function of the MC proteases has for a long time been relatively obscure. However, recent progress involving successful genetic targeting of several MC protease genes has generated powerful tools, which will enable us to unravel the role of the MC proteases both in normal physiology as well as in pathological settings. This chapter summarizes the current knowledge of the biology of the MC proteases.
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Affiliation(s)
- Gunnar Pejler
- Department of Anatomy, Physiology and Biochemistry, The Biomedical Centre, Swedish University of Agricultural Sciences, Uppsala, Sweden
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30
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Rai BK, Fiser A. Multiple mapping method: a novel approach to the sequence-to-structure alignment problem in comparative protein structure modeling. Proteins 2006; 63:644-61. [PMID: 16437570 DOI: 10.1002/prot.20835] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A major bottleneck in comparative protein structure modeling is the quality of input alignment between the target sequence and the template structure. A number of alignment methods are available, but none of these techniques produce consistently good solutions for all cases. Alignments produced by alternative methods may be superior in certain segments but inferior in others when compared to each other; therefore, an accurate solution often requires an optimal combination of them. To address this problem, we have developed a new approach, Multiple Mapping Method (MMM). The algorithm first identifies the alternatively aligned regions from a set of input alignments. These alternatively aligned segments are scored using a composite scoring function, which determines their fitness within the structural environment of the template. The best scoring regions from a set of alternative segments are combined with the core part of the alignments to produce the final MMM alignment. The algorithm was tested on a dataset of 1400 protein pairs using 11 combinations of two to four alignment methods. In all cases MMM showed statistically significant improvement by reducing alignment errors in the range of 3 to 17%. MMM also compared favorably over two alignment meta-servers. The algorithm is computationally efficient; therefore, it is a suitable tool for genome scale modeling studies.
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Affiliation(s)
- Brajesh K Rai
- Department of Biochemistry and Seaver Center for Bioinformatics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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31
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Abstract
In 1960, a trypsin-like activity was found in mast cells [Glenner GG & Cohen LA (1960) Nature 185, 846-847] and this activity is now commonly referred to as 'tryptase'. Over the years, much knowledge about mast cell tryptase has been gathered, and a recent (18 January 2006) PubMed search for the keywords 'tryptase + mast cell*' retrieved 1661 articles. However, still very little is known about its true biological function. For example, the true physiological substrate(s) for mast cell tryptase has not been identified, and the potential role of tryptase in mast cell-related disease is not understood. Mast cell tryptase has several unique features, with perhaps the most remarkable being its organization into a tetrameric state with all of the active sites oriented towards a narrow central pore and its consequent complete resistance towards endogenous macromolecular protease inhibitors. Much effort has been invested to elucidate these properties of tryptase. In this review we summarize the current knowledge of mast cell tryptase, including novel insights into its possible biological functions and mechanisms of regulation.
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Affiliation(s)
- Jenny Hallgren
- Department of Molecular Biosciences, The Biomedical Centre, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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Plager DA, Weiss EA, Kephart GM, Mocharla RM, Matsumoto R, Checkel JL, Schwartz LB, Gleich GJ, Leiferman KM. Identification of basophils by a mAb directed against pro-major basic protein 1. J Allergy Clin Immunol 2006; 117:626-34. [PMID: 16522463 DOI: 10.1016/j.jaci.2005.10.023] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2004] [Revised: 10/09/2005] [Accepted: 10/11/2005] [Indexed: 11/18/2022]
Abstract
BACKGROUND Basophils possess characteristics of both mast cells and eosinophils, and all 3 cell types often are found together, particularly during allergic reactions. A mAb (J175-7D4) generated against the recombinant pro-form of human eosinophil granule major basic protein 1 (rproMBP1) appeared to stain only basophils in tissue specimens. OBJECTIVE We investigated J175-7D4 to characterize its specificity for basophils. METHODS Fluid-phase immunoprecipitation, Western blotting, and immunocytochemistry and immunohistochemistry were used to establish the specificity of J175-7D4. RESULTS First, J175-7D4 binds to various glycosylated and proteolytically processed forms of rproMBP1, but not to major basic protein. Second, cells transfected with the rproMBP1 gene and human placental tissue (known to express the pro-form of major basic protein 1 [proMBP1]) stain specifically with J175-7D4. In contrast, although mature eosinophils contain substantial major basic protein, they lack proMBP1 and do not stain. Neutrophils, lymphocytes, monocytes, and skin mast cells also are not stained. However, blood basophils are stained by J175-7D4, anti-IgE, Wright-Giemsa (metachromatically), and a previously characterized basophil-specific mAb, 2D7. Finally, formaldehyde-fixed, paraffin-embedded basophils are identically detected by J175-7D4 and 2D7, and J175-7D4 also recognizes putative basophils in formaldehyde-fixed, paraffin-embedded tissue specimens from inflammatory dermatoses, such as atopic dermatitis and delayed pressure urticaria. CONCLUSION The J175-7D4 mAb recognizes proMBP1 as a novel marker for human basophils. J175-7D4 should prove useful for characterizing basophil involvement in human health and disease.
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Affiliation(s)
- Douglas A Plager
- Department of Dermatology, Mayo Clinic Rochester, MN, and Department of Internal Medicine, Virginia Commonwealth University, USA
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Henningsson F, Yamamoto K, Saftig P, Reinheckel T, Peters C, Knight SD, Pejler G. A role for cathepsin E in the processing of mast-cell carboxypeptidase A. J Cell Sci 2005; 118:2035-42. [PMID: 15860733 DOI: 10.1242/jcs.02333] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mast-cell carboxypeptidase A is stored in the secretory granule and is released, together with a range of other inflammatory mediators, upon mast-cell degranulation. Carboxypeptidase A, like all mast-cell proteases, is stored in the granule as an active enzyme (i.e. with its propeptide removed). Although the processing mechanisms for the other classes of mast-cell proteases (in particular the chymases) have been clarified to some extent, the processing of procarboxypeptidase A is poorly characterized. Here, we show that mast cells from mice lacking the aspartic protease cathepsin E display an accumulation of procarboxypeptidase A, indicating a defect in carboxypeptidase-A processing. By contrast, mast cells lacking cathepsins B, L or D have normal carboxypeptidase-A processing. Furthermore, recombinant cathepsin E was found to process recombinant procarboxypeptidase A in vitro, under conditions resembling those found in mast-cell granules. Immunohistochemical analysis revealed staining for cathepsin E in mast cells from normal mice but not in mast cells from mice lacking heparin, indicating that cathepsin E is bound to heparin proteoglycan within mast-cell granules. In accordance with this notion, affinity chromatography showed that recombinant cathepsin E bound strongly to heparin under acidic conditions (the conditions prevailing in mast-cell granules) but not at neutral pH. Moreover, mast-cell degranulation resulted in the release of cathepsin E. Taken together, our results indicate that cathepsin E is located in mast-cell secretory granules in complex with heparin proteoglycans, and that it has a role in the processing of procarboxypeptidase A into active protease.
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Affiliation(s)
- Frida Henningsson
- Swedish University of Agricultural Sciences, Department of Molecular Biosciences, The Biomedical Centre, Box 575, 751 23 Uppsala, Sweden
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Sebollela A, Cagliari TC, Limaverde GSCS, Chapeaurouge A, Sorgine MHF, Coelho-Sampaio T, Ramos CHI, Ferreira ST. Heparin-binding Sites in Granulocyte-Macrophage Colony-stimulating Factor. J Biol Chem 2005; 280:31949-56. [PMID: 16027123 DOI: 10.1074/jbc.m505314200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The biological activity of granulocyte-macrophage colony-stimulating factor (GM-CSF) is modulated by the sulfated glycosaminoglycans (GAGs) heparan sulfate and heparin. However, the molecular mechanisms involved in such interactions are still not completely understood. We have proposed previously that helix C, one of the four alpha-helices of human GM-CSF (hGM-CSF), contains a GAG-binding site in which positively charged residues are spatially positioned for interaction with the sulfate moieties of the GAGs (Wettreich, A., Sebollela, A., Carvalho, M. A., Azevedo, S. P., Borojevic, R., Ferreira, S. T., and Coelho-Sampaio, T. (1999) J. Biol. Chem. 274, 31468-31475). Protonation of two histidine residues (His83 and His87) in helix C of hGM-CSF appears to act as a pH-dependent molecular switch to control the interaction with GAGs. Based on these findings, we have now generated a triple mutant form of murine GM-CSF (mGM-CSF) in which three noncharged residues in helix C of the murine factor (Tyr83, Gln85, and Tyr87) were replaced by the corresponding basic residues present in hGM-CSF (His83, Lys85, and His87). Binding assays on heparin-Sepharose showed that, at acidic pH, the triple mutant mGM-CSF binds to immobilized heparin with significantly higher affinity than wild type (WT) mGM-CSF and that neither protein binds to the column at neutral pH. The fact that even WT mGM-CSF binds to heparin at acidic pH indicates the existence of a distinct, lower affinity heparin-binding site in the protein. Chemical modification of the single histidine residue (His15) located in helix A of WT mGM-CSF with diethyl pyrocarbonate totally abolished binding to immobilized heparin. Moreover, replacement of His15 for an alanine residue significantly reduced the affinity of mGM-CSF for heparin at pH 5.0 and completely blocked heparin binding to a synthetic peptide corresponding to helix A of GM-CSF. These results indicate a major role of histidine residues in the regulation of the binding of GM-CSF to GAGs, supporting the notion that an acidic microenvironment is required for GM-CSF-dependent regulation of target cells. In addition, our results provide insight into the molecular basis of the strict species specificity of the biological activity of GM-CSF.
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Affiliation(s)
- Adriano Sebollela
- Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21940-590, Brazil
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Schug KA, Lindner W. Noncovalent binding between guanidinium and anionic groups: focus on biological- and synthetic-based arginine/guanidinium interactions with phosph[on]ate and sulf[on]ate residues. Chem Rev 2005; 105:67-114. [PMID: 15720152 DOI: 10.1021/cr040603j] [Citation(s) in RCA: 459] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kevin A Schug
- University of Vienna, Department of Analytical Chemistry, Währingerstrasse 38, A-1090 Vienna, Austria.
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Yasuda S, Morokawa N, Wong GW, Rossi A, Madhusudhan MS, Sali A, Askew YS, Adachi R, Silverman GA, Krilis SA, Stevens RL. Urokinase-type plasminogen activator is a preferred substrate of the human epithelium serine protease tryptase epsilon/PRSS22. Blood 2005; 105:3893-901. [PMID: 15701722 PMCID: PMC1895090 DOI: 10.1182/blood-2003-10-3501] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Tryptase epsilon is a member of the chromosome 16p13.3 family of human serine proteases that is preferentially expressed by epithelial cells. Recombinant pro-tryptase epsilon was generated to understand how the exocytosed zymogen might be activated outside of the epithelial cell, as well as to address its possible role in normal and diseased states. Using expression/site-directed mutagenesis approaches, we now show that Lys20, Cys90, and Asp92 in the protease's substrate-binding cleft regulate its enzymatic activity. We also show that Arg(-1) in the propeptide domain controls its ability to autoactivate. In vitro studies revealed that recombinant tryptase epsilon possesses a restricted substrate specificity. Once activated, tryptase epsilon cannot be inhibited effectively by the diverse array of protease inhibitors present in normal human plasma. Moreover, this epithelium protease is not highly susceptible to alpha1-antitrypsin or secretory leukocyte protease inhibitor, which are present in the lung. Recombinant tryptase epsilon could not cleave fibronectin, vitronectin, laminin, single-chain tissue-type plasminogen activator, plasminogen, or any prominent serum protein. Nevertheless, tryptase epsilon readily converted single-chain pro-urokinase-type plasminogen activator (pro-uPA/scuPA) into its mature, enzymatically active protease. Tryptase epsilon also was able to induce pro-uPA-expressing smooth muscle cells to increase their migration through a basement membrane-like extracellular matrix. The ability to activate uPA in the presence of varied protease inhibitors suggests that tryptase epsilon plays a prominent role in fibrinolysis and other uPA-dependent reactions in the lung.
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Affiliation(s)
- Shinsuke Yasuda
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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Hallgren J, Lindahl S, Pejler G. Structural requirements and mechanism for heparin-dependent activation and tetramerization of human betaI- and betaII-tryptase. J Mol Biol 2005; 345:129-39. [PMID: 15567416 DOI: 10.1016/j.jmb.2004.10.029] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2004] [Revised: 09/29/2004] [Accepted: 10/11/2004] [Indexed: 10/26/2022]
Abstract
Tryptase, a tetrameric serine protease, is a main constituent of the secretory granules in human mast cells, where it is stored in complex with heparin or chondroitin sulfate proteoglycan. Human tryptase has been implicated in a variety of clinical conditions including asthma, but the mechanisms that lead to its tetramerization/activation have not been extensively investigated. Here we addressed the activation mechanisms for human betaI and betaII-tryptase, which differ in that betaI-tryptase is N-glycosylated at Asn102 whereas betaII-tryptase has a Lys residue at position 102, and consequently lacks the corresponding N-glycosylation. We found that both tryptases were dependent on heparin for activation/tetramerization, but whereas betaI-tryptase activation preferentially occurred at acidic pH, betaII-tryptase activation was less pH-dependent. Both betaI and betaII-tryptase bound strongly to heparin-Sepharose at acidic pH but with lower affinity at neutral pH. Further, while addition of heparin to betaI-tryptase predominantly resulted in formation of active tetrameric enzyme, betaII-tryptase showed a tendency to form inactive aggregates. betaI and betaII-tryptase were similar in that the minimal heparin size to induce activation was an octasaccharide and in that the interaction with heparin and structurally related polysaccharides was dependent on high anionic charge density rather than on specific structural motifs. Addition of decasaccharides to both betaI and betaII-tryptase resulted in the formation of active monomeric enzyme, whereas intact heparin promoted assembly of tetrameric enzyme. This, together with a bell-shaped dose response curve for heparin-induced activation, suggests that the mechanism for tetramerization involves bridging of individual tryptase monomers by heparin. Taken together, this study indicates a key role for heparin in the activation of human beta-tryptase.
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Affiliation(s)
- Jenny Hallgren
- Department of Molecular Biosciences, The Biomedical Centre, Swedish University of Agricultural Sciences, Box 575, 751 23 Uppsala, Sweden
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38
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Hallgren J, Bäckström S, Estrada S, Thuveson M, Pejler G. Histidines are critical for heparin-dependent activation of mast cell tryptase. THE JOURNAL OF IMMUNOLOGY 2004; 173:1868-75. [PMID: 15265919 DOI: 10.4049/jimmunol.173.3.1868] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mast cell tryptase is a tetrameric serine protease that is stored in complex with negatively charged heparin proteoglycans in the secretory granule. Tryptase has potent proinflammatory properties and has been implicated in diverse pathological conditions such as asthma and fibrosis. Previous studies have shown that tryptase binds tightly to heparin, and that heparin is required in the assembly of the tryptase tetramer as well as for stabilization of the active tetramer. Because the interaction of tryptase with heparin is optimal at acidic pH, we investigated in this study whether His residues are of importance for the heparin binding, tetramerization, and activation of the tryptase mouse mast cell protease 6. Molecular modeling of mouse mast cell protease 6 identified four His residues, H35, H106, H108, and H238, that are conserved among pH-dependent tryptases and are exposed on the molecular surface, and these four His residues were mutated to Ala. In addition, combinations of different mutations were prepared. Generally, the single His-Ala mutations did not cause any major defects in heparin binding, activation, or tetramerization, although some effect of the H106A mutation was observed. However, when several mutations were combined, large defects in all of these parameters were observed. Of the mutants, the triple mutant H106A/H108A/H238A was the most affected with an almost complete inability to bind to heparin and to form active tryptase tetramers. Taken together, this study shows that surface-exposed histidines mediate the interaction of mast cell tryptase with heparin and are of critical importance in the formation of active tryptase tetramers.
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Affiliation(s)
- Jenny Hallgren
- Department of Molecular Biosciences, The Biomedical Centre, Swedish University of Agricultural Sciences, Uppsala, Sweden
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39
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Bagga S, Price KS, Lin DA, Friend DS, Austen KF, Boyce JA. Lysophosphatidic acid accelerates the development of human mast cells. Blood 2004; 104:4080-7. [PMID: 15319282 DOI: 10.1182/blood-2004-03-1166] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Mast cells (MCs) initiate immune responses from mucosal surfaces and perivascular spaces. Stem cell factor (SCF) regulates MC development and viability, but the role of innate serum factors in MC development is unexplored. Cultured cord blood-derived human MCs (hMCs) express mRNA transcripts for all 4 known receptors for lysophosphatidic acid (LPA), an abundant serum-associated lipid growth factor. In an SCF-dependent serum-free culture system, LPA (2.5-10 microM) increased the total number of hMCs by approximately 10-fold compared with cultures maintained in the absence of LPA under otherwise identical conditions. LPA was comitogenic with SCF but did not prolong MC survival. LPA-mediated proliferation was blocked by VPC-32179, a competitive antagonist of LPA(1) and LPA(3) receptors, and by pertussis toxin, and it was also attenuated by GW9662, a selective antagonist of peroxisome proliferator-activated receptor (PPAR)-gamma. LPA accelerated the acquisition of hMC granules and increased Kit expression. hMCs derived in the presence of LPA were functional, as evidenced by their immunoglobulin E (IgE)-dependent histamine release and by their characteristic proliferative responses to interleukin-3 (IL-3), IL-4, and IL-9 in combination with SCF. Thus, LPA acts through LPA receptor and PPAR-gamma-dependent pathways to accelerate hMC proliferation and differentiation, and it modulates their phenotype without providing cytoprotection. LPA could facilitate MC hyperplasia in inflammation associated with either innate or adaptive immunity.
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Affiliation(s)
- Savita Bagga
- Department of Medicine, Harvard Medical School, Boston, MA, USA
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40
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Kolset SO, Prydz K, Pejler G. Intracellular proteoglycans. Biochem J 2004; 379:217-27. [PMID: 14759226 PMCID: PMC1224092 DOI: 10.1042/bj20031230] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2003] [Revised: 12/23/2003] [Accepted: 02/03/2004] [Indexed: 12/11/2022]
Abstract
Proteoglycans (PGs) are proteins with glycosaminoglycan chains, are ubiquitously expressed and have a wide range of functions. PGs in the extracellular matrix and on the cell surface have been the subject of extensive structural and functional studies. Less attention has so far been given to PGs located in intracellular compartments, although several reports suggest that these have biological functions in storage granules, the nucleus and other intracellular organelles. The purpose of this review is, therefore, to present some of these studies and to discuss possible functions linked to PGs located in different intracellular compartments. Reference will be made to publications relevant for the topics we present. It is beyond the scope of this review to cover all publications on PGs in intracellular locations.
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Affiliation(s)
- Svein Olav Kolset
- Institute for Nutrition Research, University of Oslo, Box 1046 Blindern, 0316 Oslo, Norway.
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41
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Veugelers K, Motyka B, Frantz C, Shostak I, Sawchuk T, Bleackley RC. The granzyme B–serglycin complex from cytotoxic granules requires dynamin for endocytosis. Blood 2004; 103:3845-53. [PMID: 14739229 DOI: 10.1182/blood-2003-06-2156] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Abstract
Cytotoxic T lymphocytes and natural killer cells destroy target cells via the directed exocytosis of lytic effector molecules such as perforin and granzymes. The mechanism by which these proteins enter targets is uncertain. There is ongoing debate over whether the most important endocytic mechanism is nonspecific or is dependent on the cation-independent mannose 6-phosphate receptor. This study tested whether granzyme B endocytosis is facilitated by dynamin, a key factor in many endocytic pathways. Uptake of and killing by the purified granzyme B molecule occurred by both dynamin-dependent and -independent mechanisms. However most importantly, serglycin-bound granzyme B in high-molecular-weight degranulate material from cytotoxic T lymphocytes predominantly followed a dynamin-dependent pathway to kill target cells. Similarly, killing by live cytotoxic T lymphocytes was attenuated by a defect in the dynamin endocytic pathway, and in particular, the pathways characteristically activated by granzyme B were affected. We therefore propose a model where degranulated serglycin-bound granzymes require dynamin for uptake.
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Affiliation(s)
- Kirstin Veugelers
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
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42
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Abstract
Regulated secretion and exocytosis require the selective packaging of regulated secretory proteins in secretory storage organelles and the controlled docking and fusion of these organelles with the plasma membrane. Secretory granule biogenesis involves sorting of secretory proteins and membrane components both at the level of the trans-Golgi network and the immature secretory granule. Sorting is thought to be mediated by selective protein aggregation and the interaction of these proteins with specific membrane domains. There is now considerable interest in the understanding of the complex lipid-protein and protein-protein interactions at the trans-Golgi network and the granule membrane. A role for lipid microdomains and associated sorting receptors in membrane targeting and granule formation is vividly discussed for (neuro)endocrine cells. In exocrine cells, however, little has been known of granule membrane composition and membrane protein function. With the cloning and characterization of granule membrane proteins and their interactions at the inner leaflet of zymogen granules of pancreatic acinar cells, it is now possible to elucidate their function in membrane targeting and sorting of zymogens at the molecular level.
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Affiliation(s)
- Michael Schrader
- Department of Cell Biology and Cell Pathology, University of Marburg, Robert Koch Str 6, 35037 Marburg, Germany
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Marti‐Renom MA, Madhusudhan M, Eswar N, Pieper U, Shen M, Sali A, Fiser A, Mirkovic N, John B, Stuart A. Modeling Protein Structure from its Sequence. ACTA ACUST UNITED AC 2003. [DOI: 10.1002/0471250953.bi0501s03] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Marc A. Marti‐Renom
- Departments of Biopharmaceutical Sciences and Pharmaceutical Chemistry and The California Institute for Quantitative Biomedical Research University of California at San Francisco San Francisco California
| | - M.S. Madhusudhan
- Departments of Biopharmaceutical Sciences and Pharmaceutical Chemistry and The California Institute for Quantitative Biomedical Research University of California at San Francisco San Francisco California
| | - Narayanan Eswar
- Departments of Biopharmaceutical Sciences and Pharmaceutical Chemistry and The California Institute for Quantitative Biomedical Research University of California at San Francisco San Francisco California
| | - Ursula Pieper
- Departments of Biopharmaceutical Sciences and Pharmaceutical Chemistry and The California Institute for Quantitative Biomedical Research University of California at San Francisco San Francisco California
| | - Min‐yi Shen
- Departments of Biopharmaceutical Sciences and Pharmaceutical Chemistry and The California Institute for Quantitative Biomedical Research University of California at San Francisco San Francisco California
| | - Andrej Sali
- Departments of Biopharmaceutical Sciences and Pharmaceutical Chemistry and The California Institute for Quantitative Biomedical Research University of California at San Francisco San Francisco California
| | - Andras Fiser
- Department of Biochemistry and Seaver Foundation Center for Bioinformatics Albert Einstein College of Medicine Bronx New York
| | - Nebojsa Mirkovic
- Laboratory of Molecular Biophysics The Rockefeller University New York New York
| | - Bino John
- Laboratory of Molecular Biophysics The Rockefeller University New York New York
| | - Ashley Stuart
- Laboratory of Molecular Biophysics The Rockefeller University New York New York
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Ilangumaran S, Finan D, Raine J, Rottapel R. Suppressor of cytokine signaling 1 regulates an endogenous inhibitor of a mast cell protease. J Biol Chem 2003; 278:41871-80. [PMID: 12917417 DOI: 10.1074/jbc.m308382200] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Suppressor of cytokine signaling 1 (SOCS1) is a negative regulator of c-Kit and interleukin-3 (IL-3) receptor signaling. We examined the role of SOCS1 in regulating IL-3-induced cell growth of primary bone marrow-derived mast cells (BMMCs) from SOCS1-/- mice. Instead of showing increased proliferation, SOCS1-deficient BMMCs responded poorly to IL-3 and stem cell factor. SOCS1-/- BMMCs showed increased apoptosis and defective cell cycle entry. We show that the growth retardation of SOCS1-/- BMMCs was due to a cell intrinsic defect. Protein tyrosine phosphorylation following IL-3 stimulation was markedly diminished in SOCS1-/- BMMCs. Intriguingly, JAK2 and STAT5 proteins were selectively diminished in SOCS1-/- BMMCs, which also showed lower molecular mass products of p85 and Vav suggesting proteolytic degradation. Incubation of the SOCS1-/- BMMC lysate with STAT5, p85, and Vav immunoprecipitated from SOCS1+/+ cells directly demonstrated the dysregulated proteolytic activity in SOCS1-/- BMMCs. The proteolytic activity in SOCS1-/- BMMCs was selectively inhibited by phenylmethylsulfonyl fluoride and soybean trypsin inhibitor, suggesting that the protease regulated by SOCS1 is a tryptase. The dysregulated tryptase in SOCS1-/- BMMCs is unlikely to be mMCP6 or mMCP7, because the enzyme activity was not inhibited by Polybrene but was inhibited by normal mouse plasma. SOCS1+/+ BMMC lysate inhibited the proteolytic activity present in SOCS1-/- BMMC lysate, indicating that SOCS1-/- BMMCs lack an endogenous protease inhibitor. These results show that SOCS1 is required for the expression and/or stability of an endogenous protease inhibitor, which protects mast cells from their own proteolytic enzymes.
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Affiliation(s)
- Subburaj Ilangumaran
- Ontario Cancer Institute, Princess Margaret Hospital, University Health Network, 610 University Avenue, Toronto M5G 2M9, Canada
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45
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Chen C, Darrow AL, Qi JS, D'Andrea MR, Andrade-Gordon P. A novel serine protease predominately expressed in macrophages. Biochem J 2003; 374:97-107. [PMID: 12795636 PMCID: PMC1223591 DOI: 10.1042/bj20030242] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2003] [Revised: 05/22/2003] [Accepted: 06/10/2003] [Indexed: 11/17/2022]
Abstract
We have identified a novel serine protease designated EOS by sequence identity searches. The deduced protein contains 284 amino acids with an active form containing 248 amino acids starting from an Ile-Val-Gly-Gly motif. The active form comprises a catalytic triad of conserved amino acids: His77, Asp126 and Ser231. It shares 44% identity with beta-tryptase and belongs to the S1 trypsin-like serine-protease family. Interestingly, this gene also maps to human chromosome 16p13.3. The purified protease showed amidolytic activity, cleaving its substrates before arginine residues. Tissue distribution by immunohistochemistry analysis demonstrated that EOS is highly expressed in spleen and moderately expressed in intestine, colon, lung and brain. We confirmed this expression pattern at the mRNA level by performing in situ hybridization. The results from both immunohistochemistry and in situ hybridization indicate that EOS is associated with macrophages. We corroborated this observation by double immunofluorescence using the anti-EOS antibody and an anti-CD68 antibody, a macrophage specific marker. Furthermore, we have detected a dramatic increase in immune staining of EOS in cultured U937 cells treated with PMA, which represent activated macrophages. This up-regulation is also reflected by elevated EOS mRNA in the PMA-treated U937 cells detected by Northern blotting. Since macrophages have important roles in various pathological conditions, such as wound healing, atherosclerosis and numerous inflammatory diseases, the localization of this novel serine protease to active macrophages may help to further the elucidation of the roles of this gene product in modulating these disorders.
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Affiliation(s)
- Cailin Chen
- Drug Discovery, Johnson & Johnson Pharmaceutical Research and Development LLC, Welsh and McKean Roads, Spring House, PA 19477-0776, USA
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46
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John B, Sali A. Comparative protein structure modeling by iterative alignment, model building and model assessment. Nucleic Acids Res 2003; 31:3982-92. [PMID: 12853614 PMCID: PMC165975 DOI: 10.1093/nar/gkg460] [Citation(s) in RCA: 264] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Comparative or homology protein structure modeling is severely limited by errors in the alignment of a modeled sequence with related proteins of known three-dimensional structure. To ameliorate this problem, we have developed an automated method that optimizes both the alignment and the model implied by it. This task is achieved by a genetic algorithm protocol that starts with a set of initial alignments and then iterates through re-alignment, model building and model assessment to optimize a model assessment score. During this iterative process: (i) new alignments are constructed by application of a number of operators, such as alignment mutations and cross-overs; (ii) comparative models corresponding to these alignments are built by satisfaction of spatial restraints, as implemented in our program MODELLER; (iii) the models are assessed by a variety of criteria, partly depending on an atomic statistical potential. When testing the procedure on a very difficult set of 19 modeling targets sharing only 4-27% sequence identity with their template structures, the average final alignment accuracy increased from 37 to 45% relative to the initial alignment (the alignment accuracy was measured as the percentage of positions in the tested alignment that were identical to the reference structure-based alignment). Correspondingly, the average model accuracy increased from 43 to 54% (the model accuracy was measured as the percentage of the C(alpha) atoms of the model that were within 5 A of the corresponding C(alpha) atoms in the superposed native structure). The present method also compares favorably with two of the most successful previously described methods, PSI-BLAST and SAM. The accuracy of the final models would be increased further if a better method for ranking of the models were available.
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Affiliation(s)
- Bino John
- Laboratory of Molecular Biophysics, Pels Family Center for Biochemistry and Structural Biology, The Rockefeller University, New York, NY 10021, USA
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47
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Biederbick A, Licht A, Kleene R. Serglycin proteoglycan is sorted into zymogen granules of rat pancreatic acinar cells. Eur J Cell Biol 2003; 82:19-29. [PMID: 12602945 DOI: 10.1078/0171-9335-00287] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Serglycin is known as a secretory granule proteoglyean in hematopoietic cells. In this study we identified a high-molecular-weight molecule in aggregated content proteins of zymogen granules of pancreatic acinar cells. The amino acid composition of the isolated protein showed high similarity to serglycin proteoglycan core protein. To confirm the expression of serglycin proteoglycan in pancreatic acinar cells we cloned the rat pancreas cDNA of serglycin core protein and detected the serglycin mRNA in pancreas tissue and AR4-2J cells by reverse transcription-PCR. In AR4-2J cells, transfected with serglycin fused to green fluorescent protein (EGFP), serglycin localized within a web-like pattern in the perinuclear space as well as with a punctate pattern distributed in the cytoplasm. The perinuclear structures colocalized with the Golgi membrane-associated protein p115 and the punctate structures with the secretory enzyme procarboxypeptidase A, indicating that the serglycin-EGFP fusion protein travels through compartments of the secretory pathway and is sorted into secretory granules. Using an antiserum against serglycin core protein immunofluorescence as well as immunogold electron microscopy analysis conrirmed the subcellular distribution of serglycin proteoglycan in zymogen granules of pancreatic acinar cells. To prevent glycosylation of serglycin core protein we incubated AR4-2J cells with 2 mM p-nitrophenyl-beta-D-xylopyranoside (PNP-xyloside), which serves as alternate substrate for glycosaminoglycan chain attachment. Furthermore, we deleted the serine/glycine repeat region in the serglycin core protein. In both approaches the transfected serglycin-EGFP fusion protein could be detected predominantly in perinuclear Golgi membrane structures, while in control cells the serglycin fusion protein was mostly sorted into the secretory granules. Additionally, we show that sorting of secretory enzymes like amylase
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Affiliation(s)
- Annette Biederbick
- Department of Cell Biology and Cell Pathology, Philipps University, Marburg, Germany.
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Raja SM, Wang B, Dantuluri M, Desai UR, Demeler B, Spiegel K, Metkar SS, Froelich CJ. Cytotoxic cell granule-mediated apoptosis. Characterization of the macromolecular complex of granzyme B with serglycin. J Biol Chem 2002; 277:49523-30. [PMID: 12388539 DOI: 10.1074/jbc.m209607200] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have recently shown that the physiological mediator of granule-mediated apoptosis is a macromolecular complex of granzymes and perforin complexed with the chondroitin-sulfate proteoglycan, serglycin (Metkar, S. S., Wang, B., Aguilar-Santelises, M., Raja, S. M., Uhlin-Hansen, L., Podack, E., Trapani, J. A., and Froelich, C. J. (2002) Immunity 16, 417-428). We now report our biophysical studies establishing the nature of granzyme B-serglycin (GrB.SG) complex. Dynamic laser light scattering studies establish that SG has a hydrodynamic radius of approximately 140 +/- 23 nm, comparable to some viral particles. Agarose mobility shift gels and surface plasmon resonance (SPR), show that SG binds tightly to GrB and has the capacity to hold 30-60 GrB molecules. SPR studies also indicate equivalent binding affinities (K(d) approximately 0.8 microm), under acidic (granule pH) and neutral isotonic conditions (extra-cytoplasmic pH), for GrB.SG interaction. Finally, characterization of GrB.SG interactions within granules revealed complexes of two distinct molecular sizes, one held approximately 4-8 molecules of GrB, whereas the other contained as many as 32 molecules of GrB or other granule proteins. These studies provide a firm biophysical basis for our earlier reported observations that the proapoptotic granzyme is exocytosed predominantly as a macromolecular complex with SG.
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Affiliation(s)
- Srikumar M Raja
- Department of Medicine, Evanston Northwestern Healthcare Research Institute, 2650 Ridge Avenue, Evanston, Illinois 60201, USA.
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Buczek-Thomas JA, Chu CL, Rich CB, Stone PJ, Foster JA, Nugent MA. Heparan sulfate depletion within pulmonary fibroblasts: implications for elastogenesis and repair. J Cell Physiol 2002; 192:294-303. [PMID: 12124775 DOI: 10.1002/jcp.10135] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We investigated the role of sulfated proteoglycans in regulating extracellular matrix (ECM) deposition in pulmonary fibroblast cultures. Fibroblast cultures were subject to pharmacologic and enzymatic interventions to modify sulfated proteoglycan levels. Native and proteoglycan-depleted fibroblasts were treated with porcine pancreatic elastase at 2-4-day intervals and the elastase-mediated release of fibroblast growth factor 2 (FGF-2) and glycosaminoglycans was determined. Elastase treatment released significantly less FGF-2 and glycosaminoglycans (GAG) from PG-depleted fibroblasts with respect to native cells. Equilibrium ligand binding studies indicated that 125I FGF-2 binding at both cell surface receptor and heparan sulfate proteoglycan sites was reduced to different extents based on the method of proteoglycan depletion. Quantitation of elastin protein and message levels indicated that biological sulfation is required for the proper incorporation of tropoelastin into the extracellular matrix. These results suggest that sulfated proteoglycans play a central role in modulating pulmonary fibroblast extracellular matrix composition and are important mediators of elastolytic injury.
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Affiliation(s)
- Jo Ann Buczek-Thomas
- Department of Biochemistry, Boston University School of Medicine, Massachusetts 02118, USA
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Rivera V, Levieux A, Levieux D. Characterisation of Ag1, the major species-specific contaminant of bovine crude heparin, and its identification as an aprotinin/heparin complex. J Pharm Biomed Anal 2002; 29:443-58. [PMID: 12062645 DOI: 10.1016/s0731-7085(02)00084-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Heparin is a potent anticoagulant polysaccharide purified for decades from ruminants or porcine tissues. However, with the emergence of bovine spongiform encephalopathy (BSE), the source of pharmaceutical heparin is currently restricted to porcine intestinal mucosa. A major species-specific contaminant, called Ag1, has recently been identified in bovine crude heparin [Rivera et al., J. Pharm. Biomed. Anal., submitted] and used to develop an enzyme-linked immunosorbent assay (ELISA) for the species origin control of crude heparins [Levieux et al., J. Immunoassay, submitted]. In this report, we describe the different investigations, which were carried out to identify Ag1. This antigen was first localised by immunohistological studies essentially in the connective tissue of the bovine small intestine. After extraction from an intestinal extract by immuno-affinity chromatography, Ag1 was isolated as a single band by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Ag1 was then partly sequenced and identified as an aprotinin/heparin complex. Aprotinin, also known as the bovine pancreatic trypsin inhibitor (BPTI), is present with heparin in mast cells, and is very resistant to heat, pH, chemical treatments and proteolytic digestion. The stability of Ag1 towards the different treatments performed during heparin extraction process allows this protein to remain in sufficient amounts in crude heparin and makes it an ideal target for the immunochemical control of the absence of bovine material in crude heparins.
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Affiliation(s)
- Vincent Rivera
- INRA, Station de Recherches sur la Viande, Immunochimie, Theix, 63122 Saint-Genès-Champanelle, France
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