The Experts below are selected from a list of 47841 Experts worldwide ranked by ideXlab platform
Christine M Szymanski - One of the best experts on this subject based on the ideXlab platform.
-
Deletion of a single glycosyltransferase in Caldicellulosiruptor bescii eliminates Protein Glycosylation and growth on crystalline cellulose.
Biotechnology for biofuels, 2018Co-Authors: Jordan F. Russell, Christine M Szymanski, Harald Nothaft, Sun-ki Kim, Justin Duma, Michael E. Himmel, Yannick J. Bomble, Janet WestphelingAbstract:Protein Glycosylation pathways have been identified in a variety of bacteria and are best understood in pathogens and commensals in which the Glycosylation targets are cell surface Proteins, such as S layers, pili, and flagella. In contrast, very little is known about the Glycosylation of bacterial enzymes, especially those secreted by cellulolytic bacteria. Caldicellulosiruptor bescii secretes several unique synergistic multifunctional biomass-degrading enzymes, notably cellulase A which is largely responsible for this organism’s ability to grow on lignocellulosic biomass without the conventional pretreatment. It was recently discovered that extracellular CelA is heavily glycosylated. In this work, we identified an O-glycosyltransferase in the C. bescii chromosome and targeted it for deletion. The resulting mutant was unable to grow on crystalline cellulose and showed no detectable Protein Glycosylation. Multifunctional biomass-degrading enzymes in this strain were rapidly degraded. With the genetic tools available in C. bescii, this system represents a unique opportunity to study the role of bacterial enzyme Glycosylation as well an investigation of the pathway for Protein Glycosylation in a non-pathogen.
-
N-linked Protein Glycosylation in Campylobacter
Campylobacter, 2014Co-Authors: Harald Nothaft, Saba Amber, Markus Aebi, Christine M SzymanskiAbstract:N-linked Protein Glycosylation is the most common type of Protein modification in eukaryotes and is the topic of this chapter. The chapter demonstrates that the Campylobacter jejuni glycome is an excellent toolbox for glycobiologists to understand the fundamentals of this pathway, to develop new techniques for glycobiology, and to exploit this pathway for novel diagnostics and therapeutics. A section summarizes the N-linked Proteins identified so far and provides further information on the roles for the posttranslational modification in Campylobacter which involves in cellular function. The importance of CjaA for the in vivo survival of Campylobacter has recently been shown in chicken colonization studies: birds immunized with an avirulent strain of Salmonella expressing plasmid-borne cjaA showed reduced C. jejuni colonization. In addition, gene clusters corresponding to the N-linked Protein Glycosylation pathway were shown to be present in various isolates of C. jejuni, C. lari RM2100, C. upsaliensis RM3195, C. jejuni subsp. doylei 269.97, C. coli RM2228, C. hominis ATCC BAA-381, C. curvus 525.92, C. concisus 13826, and C. fetus subsp. fetus 82-40, demonstrating that this pathway and potentially the bacillosamine-containing heptasaccharide are conserved among all Campylobacter species. C. jejuni provides researchers with an excellent model system because this organism has both well-characterized O-linked and N-linked Protein Glycosylation systems.
-
Protein Glycosylation in bacteria: sweeter than ever
Nature Reviews Microbiology, 2010Co-Authors: Harald Nothaft, Christine M SzymanskiAbstract:Glycosylation, the most abundant polypeptide chain modification in nature, was first identified in bacteria and archaea in the 1970s. Here, Nothaft and Szymanski review recent progress in our understanding of the bacterial N -Glycosylation and O -Glycosylation systems. Recent progress has been made in understanding N -linked Protein Glycosylation in Campylobacter jejuni . New N -Glycosylation pathways similar to that found in C. jejuni have now been identified in other species. A new N -Glycosylation pathway in Haemophilus influenzae has been characterized and found to function in the bacterial cytoplasm; this pathway does not involve block transfer of sugars from a lipid carrier. Bacterial O -Glycosylation pathways have also been studied, with a focus on flagellin and pilin modification systems. Recently, it has been demonstrated that particular bacterial O -Glycosylation pathways also modify multiple Proteins with glycans transferred en bloc from a lipid carrier. Bacterial Protein modification has an important biological role. Furthermore, these biosynthesis pathways can be manipulated to engineer recombinant glycoProteins with potential commercial value, and there are several emerging methods for the characterization of these systems. Investigations into bacterial Protein Glycosylation continue to progress rapidly. It is now established that bacteria possess both N -linked and O -linked Glycosylation pathways that display many commonalities with their eukaryotic and archaeal counterparts as well as some unexpected variations. In bacteria, Protein Glycosylation is not restricted to pathogens but also exists in commensal organisms such as certain Bacteroides species, and both the N -linked and O -linked Glycosylation pathways can modify multiple Proteins. Improving our understanding of the intricacies of bacterial Protein Glycosylation systems should lead to new opportunities to manipulate these pathways in order to engineer glycoProteins with potential value as novel vaccines.
-
Protein Glycosylation in bacteria: sweeter than ever.
Nature reviews. Microbiology, 2010Co-Authors: Harald Nothaft, Christine M SzymanskiAbstract:Investigations into bacterial Protein Glycosylation continue to progress rapidly. It is now established that bacteria possess both N-linked and O-linked Glycosylation pathways that display many commonalities with their eukaryotic and archaeal counterparts as well as some unexpected variations. In bacteria, Protein Glycosylation is not restricted to pathogens but also exists in commensal organisms such as certain Bacteroides species, and both the N-linked and O-linked Glycosylation pathways can modify multiple Proteins. Improving our understanding of the intricacies of bacterial Protein Glycosylation systems should lead to new opportunities to manipulate these pathways in order to engineer glycoProteins with potential value as novel vaccines.
-
N-Linked Protein Glycosylation in a Bacterial System
Methods in molecular biology (Clifton N.J.), 2009Co-Authors: Harald Nothaft, Xin Liu, David J. Mcnally, Christine M SzymanskiAbstract:N-Linked Protein Glycosylation is conserved throughout the three domains of life and influences Protein function, stability, and Protein complex formation. N-Linked Glycosylation is an essential process in Eukaryotes; however, although N-Glycosylation affects multiple cellular processes in Archaea and Bacteria, it is not needed for cell survival. Methods for the analyses of N-Glycosylation in eukaryotes are well established, but comparable techniques for the analyses of the pathways in Bacteria and Archaea are needed. In this chapter we describe new methods for the detection and analyses of N-linked, and the recently discovered free oligosaccharides (fOS), from whole cell lysates of Campylobacter jejuni using non-specific pronase E digestion and permethylation followed by mass spectrometry. We also describe the expression and immunodetection of the model N-glycoProtein, AcrA, fused to a hexa-histidine tag to follow Protein Glycosylation in C. jejuni. This chapter concludes with the recent demonstration that high-resolution magic angle spinning NMR of intact bacterial cells provides a rapid, non-invasive method for analyzing fOS in C. jejuni in vivo. This combination of techniques provides a powerful tool for the exploration, quantification, and structural analyses of N-linked and free oligosaccharides in the bacterial system.
Yanzhuang Wang - One of the best experts on this subject based on the ideXlab platform.
-
Regulation of Protein Glycosylation and sorting by the Golgi matrix Proteins GRASP55/65
Nature communications, 2013Co-Authors: Yi Xiang, Xiaoyan Zhang, David B. Nix, Toshihiko Katoh, Kazuhiro Aoki, Michael Tiemeyer, Yanzhuang WangAbstract:The Golgi receives the entire output of newly synthesized cargo from the endoplasmic reticulum, processes it in the stack largely through modification of bound oligosaccharides, and sorts it in the trans-Golgi network. GRASP65 and GRASP55, two Proteins localized to the Golgi stack and early secretory pathway, mediate processes including Golgi stacking, Golgi ribbon linking and unconventional secretion. Previously, we have shown that GRASP depletion in cells disrupts Golgi stack formation. Here we report that knockdown of the GRASP Proteins, alone or combined, accelerates Protein trafficking through the Golgi membranes but also has striking negative effects on Protein Glycosylation and sorting. These effects are not caused by Golgi ribbon unlinking, unconventional secretion or endoplasmic reticulum stress. We propose that GRASP55/65 are negative regulators of exocytic transport and that this slowdown helps to ensure more complete Protein Glycosylation in the Golgi stack and proper sorting at the trans-Golgi network.
-
regulation of Protein Glycosylation and sorting by the golgi matrix Proteins grasp55 65
Nature Communications, 2013Co-Authors: Yi Xiang, Xiaoyan Zhang, David B. Nix, Toshihiko Katoh, Kazuhiro Aoki, Michael Tiemeyer, Yanzhuang WangAbstract:The Golgi receives the entire output of newly synthesized cargo from the endoplasmic reticulum, processes it in the stack largely through modification of bound oligosaccharides, and sorts it in the trans-Golgi network. GRASP65 and GRASP55, two Proteins localized to the Golgi stack and early secretory pathway, mediate processes including Golgi stacking, Golgi ribbon linking and unconventional secretion. Previously, we have shown that GRASP depletion in cells disrupts Golgi stack formation. Here we report that knockdown of the GRASP Proteins, alone or combined, accelerates Protein trafficking through the Golgi membranes but also has striking negative effects on Protein Glycosylation and sorting. These effects are not caused by Golgi ribbon unlinking, unconventional secretion or endoplasmic reticulum stress. We propose that GRASP55/65 are negative regulators of exocytic transport and that this slowdown helps to ensure more complete Protein Glycosylation in the Golgi stack and proper sorting at the trans-Golgi network.
Yi Xiang - One of the best experts on this subject based on the ideXlab platform.
-
Regulation of Protein Glycosylation and sorting by the Golgi matrix Proteins GRASP55/65
Nature communications, 2013Co-Authors: Yi Xiang, Xiaoyan Zhang, David B. Nix, Toshihiko Katoh, Kazuhiro Aoki, Michael Tiemeyer, Yanzhuang WangAbstract:The Golgi receives the entire output of newly synthesized cargo from the endoplasmic reticulum, processes it in the stack largely through modification of bound oligosaccharides, and sorts it in the trans-Golgi network. GRASP65 and GRASP55, two Proteins localized to the Golgi stack and early secretory pathway, mediate processes including Golgi stacking, Golgi ribbon linking and unconventional secretion. Previously, we have shown that GRASP depletion in cells disrupts Golgi stack formation. Here we report that knockdown of the GRASP Proteins, alone or combined, accelerates Protein trafficking through the Golgi membranes but also has striking negative effects on Protein Glycosylation and sorting. These effects are not caused by Golgi ribbon unlinking, unconventional secretion or endoplasmic reticulum stress. We propose that GRASP55/65 are negative regulators of exocytic transport and that this slowdown helps to ensure more complete Protein Glycosylation in the Golgi stack and proper sorting at the trans-Golgi network.
-
regulation of Protein Glycosylation and sorting by the golgi matrix Proteins grasp55 65
Nature Communications, 2013Co-Authors: Yi Xiang, Xiaoyan Zhang, David B. Nix, Toshihiko Katoh, Kazuhiro Aoki, Michael Tiemeyer, Yanzhuang WangAbstract:The Golgi receives the entire output of newly synthesized cargo from the endoplasmic reticulum, processes it in the stack largely through modification of bound oligosaccharides, and sorts it in the trans-Golgi network. GRASP65 and GRASP55, two Proteins localized to the Golgi stack and early secretory pathway, mediate processes including Golgi stacking, Golgi ribbon linking and unconventional secretion. Previously, we have shown that GRASP depletion in cells disrupts Golgi stack formation. Here we report that knockdown of the GRASP Proteins, alone or combined, accelerates Protein trafficking through the Golgi membranes but also has striking negative effects on Protein Glycosylation and sorting. These effects are not caused by Golgi ribbon unlinking, unconventional secretion or endoplasmic reticulum stress. We propose that GRASP55/65 are negative regulators of exocytic transport and that this slowdown helps to ensure more complete Protein Glycosylation in the Golgi stack and proper sorting at the trans-Golgi network.
Brendan W Wren - One of the best experts on this subject based on the ideXlab platform.
-
Protein Glycosylation in bacterial mucosal pathogens
Nature Reviews Microbiology, 2005Co-Authors: Christine M Szymanski, Brendan W WrenAbstract:It is now apparent that organisms from all three domains of life are capable of modifying their Proteins through Glycosylation. Similar processes of glycoconjugate biosynthesis are conserved among all three domains by segregating key steps of the pathway with membranes, by the use of nucleotide-activated and/or lipid-linked intermediates, and by transfer of sugars to the same amino acid sequons. Among Bacteria, mucosal pathogens have a particular propensity to glycosylate surface structures. Mucosal pathogens frequently share similar sugar biosynthetic genes, resulting in similar glycans such as bacillosamine- and pseudaminic acid-like structures. Campylobacter jejuni is unique among Bacteria as it has well-characterized O - and N -linked Glycosylation systems. The recent demonstration of the transfer of the Campylobacter N -linked Glycosylation pathway into Escherichia coli opens up the possibility of producing recombinant glycoProteins. Together with the detailed characterization of several bacterial Glycosylation pathways, the opportunity to engineer countless permutations of novel glycoProteins in a simple E. coli host is now possible. Further characterization of the Campylobacter O - and N -linked Glycosylation systems and other bacterial systems will provide useful models to study more complex eukaryotic Protein Glycosylation pathways. In eukaryotes, glycosylated Proteins are ubiquitous components of extracellular matrices and cellular surfaces. Their oligosaccharide moieties are implicated in a wide range of cell?cell and cell?matrix recognition events that are required for biological processes ranging from immune recognition to cancer development. Glycosylation was previously considered to be restricted to eukaryotes; however, through advances in analytical methods and genome sequencing, there have been increasing reports of both O -linked and N -linked Protein Glycosylation pathways in bacteria, particularly amongst mucosal-associated pathogens. Studying Glycosylation in relatively less-complicated bacterial systems provides the opportunity to elucidate and exploit glycoProtein biosynthetic pathways. We will review the genetic organization, glycan structures and function of Glycosylation systems in mucosal bacterial pathogens, and speculate on how this knowledge may help us to understand Glycosylation processes in more complex eukaryotic systems and how it can be used for glycoengineering.
-
Protein Glycosylation in bacterial mucosal pathogens
Nature Reviews Microbiology, 2005Co-Authors: Christine M Szymanski, Brendan W WrenAbstract:In eukaryotes, glycosylated Proteins are ubiquitous components of extracellular matrices and cellular surfaces. Their oligosaccharide moieties are implicated in a wide range of cell-cell and cell-matrix recognition events that are required for biological processes ranging from immune recognition to cancer development. Glycosylation was previously considered to be restricted to eukaryotes; however, through advances in analytical methods and genome sequencing, there have been increasing reports of both O-linked and N-linked Protein Glycosylation pathways in bacteria, particularly amongst mucosal-associated pathogens. Studying Glycosylation in relatively less-complicated bacterial systems provides the opportunity to elucidate and exploit glycoProtein biosynthetic pathways. We will review the genetic organization, glycan structures and function of Glycosylation systems in mucosal bacterial pathogens, and speculate on how this knowledge may help us to understand Glycosylation processes in more complex eukaryotic systems and how it can be used for glycoengineering.
Gordan Lauc - One of the best experts on this subject based on the ideXlab platform.
-
Evolutional and clinical implications of the epigenetic regulation of Protein Glycosylation
Clinical epigenetics, 2011Co-Authors: Tomislav Horvat, Vlatka Zoldoš, Gordan LaucAbstract:Protein N Glycosylation is an ancient posttranslational modification that enriches Protein structure and function. The addition of one or more complex oligosaccharides (glycans) to the backbones of the majority of eukaryotic Proteins makes the glycoproteome several orders of magnitude more complex than the proteome itself. Contrary to polypeptides, which are defined by a sequence of nucleotides in the corresponding genes, glycan parts of glycoProteins are synthesized by the activity of hundreds of factors forming a complex dynamic network. These are defined by both the DNA sequence and the modes of regulating gene expression levels of all the genes involved in N Glycosylation. Due to the absence of a direct genetic template, glycans are particularly versatile and apparently a large part of human variation derives from differences in Protein Glycosylation. However, composition of the individual glycome is temporally very constant, indicating the existence of stable regulatory mechanisms. Studies of epigenetic mechanisms involved in Protein Glycosylation are still scarce, but the results suggest that they might not only be important for the maintenance of a particular glycophenotype through cell division and potentially across generations but also for the introduction of changes during the adaptive evolution.
-
Protein Glycosylation--an evolutionary crossroad between genes and environment.
Molecular bioSystems, 2010Co-Authors: Gordan Lauc, Vlatka ZoldošAbstract:The majority of molecular processes in higher organisms are performed by various Proteins and are thus determined by genes that encode these Proteins. However, a significant structural component of at least half of all cellular Proteins is not a polypeptide encoded by a single gene, but an oligosaccharide (glycan) synthesized by a network of Proteins, resulting from the expression of hundreds of different genes. Relationships between hundreds of individual Proteins that participate in glycan biosynthesis are very complex which enables the influence of environmental factors on the final structure of glycans, either by direct effects on individual enzymatic processes, or by induction of epigenetic changes that modify gene expression patterns. Until recently, the complexity of glycan structures prevented large scale studies of Protein Glycosylation, but recent advances in both glycan analysis and genotyping technologies, enabled the first insights into the intricate field of complex genetics of Protein Glycosylation. Mutations which inactivate genes involved in the synthesis of common N-glycan precursors are embryonically lethal. However, mutations in genes involved in modifications of glycan antennas are common and apparently contribute largely to individual phenotypic variations that exist in humans and other higher organisms. Some of these variations can be recognized as specific glyco-phenotypes that might represent specific evolutionary advantages or disadvantages. They are however, amenable to environmental influences and are thus less pre-determined than classical Mendelian mutations.
-
Epigenetic regulation of Protein Glycosylation.
Biomolecular concepts, 2010Co-Authors: Vlatka Zoldoš, Srđana Grgurević, Gordan LaucAbstract:Protein N-Glycosylation is an ancient metabolic pathway that still exists in all three domains of life (Archaea, Bacteria and Eukarya). The covalent addition of one or more complex oligosaccharides (glycans) to Protein backbones greatly diversifies their structures and makes the glycoproteome several orders of magnitude more complex than the proteome itself. Contrary to polypeptides, which are defined by a sequence of nucleotides in the corresponding genes, the glycan part of glycoProteins are encoded in a complex dynamic network of hundreds of Proteins, whereby activity is defined by both genetic sequence and the regulation of gene expression. Owing to the complex nature of their biosynthesis, glycans are particularly versatile and apparently a large part of human variation derives from differences in Protein Glycosylation. Composition of the individual glycome appears to be rather stable, and thus differences in the pattern of glycan synthesis between individuals could originate either from genetic polymorphisms or from stable epigenetic regulation of gene expression in different individuals. Studies of epigenetic modification of genes involved in Protein Glycosylation are still scarce, but their results indicate that this process might be very important for the regulation of Protein Glycosylation.
-
Complex genetic regulation of Protein Glycosylation.
Molecular bioSystems, 2009Co-Authors: Gordan Lauc, Igor Rudan, Harry Campbell, Pauline M. RuddAbstract:One hundred years have passed since Archibald Garrod postulated the one gene/one enzyme hypothesis. Since then, science has made significant progress and geneticists are now tackling an overwhelming complexity of gene regulation networks that underlie the genetics of complex human diseases. A particularly complex element in the biology of higher organisms is the genetics of Protein Glycosylation. Nearly all Proteins that appeared after the emergence of multicellular life are glycosylated, but instead of being molded by a single gene, glycan structures are encoded within a network of several hundred glycosyltransferases, glycosidases, transporters, transcription factors and other Proteins. In addition, in contrast to the linear structures of DNA and Proteins, glycans have multiple branches that make their analysis significantly more challenging. However, recent developments in high throughput HPLC analysis have advanced glycan analysis significantly and it is now possible to address questions about the complex genetics of Protein Glycosylation. In this review we present some preliminary insights into this fascinating field.
