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Biochimica Et Biophysica Acta. General... Sep 2023The remarkable structural diversity of glycans that is exposed at the cell surface and generated along the secretory pathway is tightly regulated by several factors. The... (Review)
Review
The remarkable structural diversity of glycans that is exposed at the cell surface and generated along the secretory pathway is tightly regulated by several factors. The recent identification of human glycosylation diseases related to metal transporter defects opened a completely new field of investigation, referred to herein as "metalloglycobiology", on how metal changes can affect the glycosylation and hence the glycan structures that are produced. Although this field is in its infancy, this review aims to go through the different glycosylation steps/pathways that are metal dependent and that could be impacted by metal homeostasis dysregulations.
Topics: Humans; Cation Transport Proteins; Congenital Disorders of Glycosylation; Endoplasmic Reticulum; Glycomics; Glycosylation; Golgi Apparatus; Homeostasis; Magnesium; Metals; Oxidation-Reduction; Polysaccharides; Zinc
PubMed: 37348823
DOI: 10.1016/j.bbagen.2023.130412 -
Biochimica Et Biophysica Acta. General... Nov 2023Antibodies can mediate immune recruitment or clearance of immune complexes through the interaction of their Fc domain with cellular Fc receptors. Clustering of... (Review)
Review
Antibodies can mediate immune recruitment or clearance of immune complexes through the interaction of their Fc domain with cellular Fc receptors. Clustering of antibodies is a key step in generating sufficient avidity for efficacious receptor recognition. However, Fc receptors may be saturated with prevailing, endogenous serum immunoglobulin and this raises the threshold by which cellular receptors can be productively engaged. Here, we review the factors controlling serum IgG levels in both healthy and disease states, and discuss how the presence of endogenous IgG is encoded into the functional activation thresholds for low- and high-affinity Fc receptors. We discuss the circumstances where antibody engineering can help overcome these physiological limitations of therapeutic antibodies. Finally, we discuss how the pharmacological control of Fc receptor saturation by endogenous IgG is emerging as a feasible mechanism for the enhancement of antibody therapeutics.
Topics: Receptors, Fc; Immunoglobulin G; Receptors, IgG; Immunoglobulin Fc Fragments; Glycosylation
PubMed: 37652365
DOI: 10.1016/j.bbagen.2023.130448 -
Nature Communications Aug 2023Structure-guided immunofocusing HIV-1 vaccine design entails a comprehensive understanding of Envs from diverse HIV-1 subtypes, including circulating recombinant forms...
Structure-guided immunofocusing HIV-1 vaccine design entails a comprehensive understanding of Envs from diverse HIV-1 subtypes, including circulating recombinant forms (CRFs). Here, we present the cryo-EM structures of Envs from two Asia prevalent CRFs (CRF01_AE and CRF07_BC) at 3.0 and 3.5 Å. We compare the structures and glycosylation patterns of Envs from different subtypes and perform cross-clade statistical analyses to reveal the unique features of CRF01_AE V1 region, which are associated with the resistance to certain bNAbs. We also solve a 4.1 Å cryo-EM structure of CRF01_AE Env in complex with F6, the first bNAb from CRF01_AE-infected individuals. F6 recognizes a gp120-gp41 spanning epitope to allosterically destabilize the Env trimer apex and weaken inter-protomer packing, which in turn hinders the receptor binding and induces Env trimer disassembly, demonstrating a dual mechanism of neutralization. These findings broaden our understanding of CRF Envs and shed lights on immunofocusing HIV-1 vaccine design.
Topics: Humans; HIV-1; Genes, env; Protein Binding; Glycosylation; Broadly Neutralizing Antibodies; Vaccines; HIV Infections; HIV Antibodies; env Gene Products, Human Immunodeficiency Virus; Antibodies, Neutralizing
PubMed: 37542068
DOI: 10.1038/s41467-023-40321-x -
BioRxiv : the Preprint Server For... Sep 2023All protein simulations are conducted with varying degrees of simplifications, oftentimes with unknown ramifications on how these simplifications affect the...
All protein simulations are conducted with varying degrees of simplifications, oftentimes with unknown ramifications on how these simplifications affect the interpretability of the results. In this work we investigated how protein glycosylation and lateral crowding effects modulate an array of properties characterizing the stability and dynamics of influenza neuraminidase. We constructed three systems: 1) Glycosylated neuraminidase in a whole virion (i.e. crowded membrane) environment 2) Glycosylated neuraminidase in its own lipid bilayer 3) Unglycosylated neuraminidase in its own lipid bilayer. We saw that glycans tend to stabilize the protein structure and reduce its conformational flexibility while restricting solvent movement. Conversely, a crowded membrane environment encouraged exploration of the free energy landscape and a large scale conformational change while making the protein structure more compact. Understanding these effects informs what factors one must consider while attempting to recapture the desired level of physical accuracy.
PubMed: 37745347
DOI: 10.1101/2023.09.10.556910 -
Biotechnology Advances Dec 2023Traditionally, recombinant protein production has been done in several expression hosts of bacteria, fungi, and majorly CHO (Chinese Hamster Ovary) cells; few have high... (Review)
Review
Traditionally, recombinant protein production has been done in several expression hosts of bacteria, fungi, and majorly CHO (Chinese Hamster Ovary) cells; few have high production costs and are susceptible to harmful toxin contamination. Green algae have the potential to produce recombinant proteins in a more sustainable manner. Microalgal diversity leads to offer excellent opportunities to produce glycosylated antibodies. An antibody with humanized glycans plays a crucial role in cellular communication that works to regulate cells and molecules, to control disease, and to stimulate immunity. Therefore, it becomes necessary to understand the role of abiotic factors (light, temperature, pH, etc.) in the production of bioactive molecules and molecular mechanisms of product synthesis from microalgae which would lead to harnessing the potential of algal bio-refinery. However, the potential of microalgae as the source of bio-refinery has been less explored. In the present review, omics approaches for microalgal engineering, methods of humanized glycoproteins production focusing majorly on N-glycosylation pathways, light-based regulation of glycosylation machinery, and production of antibodies with humanized glycans in microalgae with a major emphasis on modulation of post-translation machinery of microalgae which might play a role in better understanding of microalgal potential as a source for antibody production along with future perspectives.
Topics: Cricetinae; Animals; Biotechnology; Glycosylation; CHO Cells; Cricetulus; Recombinant Proteins; Polysaccharides
PubMed: 37813174
DOI: 10.1016/j.biotechadv.2023.108267 -
Cellular & Molecular Immunology Aug 2023T-cell development ensures the formation of diverse repertoires of T-cell receptors (TCRs) that recognize a variety of antigens. Glycosylation is a major...
T-cell development ensures the formation of diverse repertoires of T-cell receptors (TCRs) that recognize a variety of antigens. Glycosylation is a major posttranslational modification present in virtually all cells, including T-lymphocytes, that regulates activity/functions. Although these structures are known to be involved in TCR-selection in DP thymocytes, it is unclear how glycans regulate other thymic development processes and how they influence susceptibility to disease. Here, we discovered stage-specific glycome compositions during T-cell development in human and murine thymocytes, as well as dynamic alterations. After restricting the N-glycosylation profile of thymocytes to high-mannose structures, using specific glycoengineered mice (Rag1Mgat1), we showed remarkable defects in key developmental checkpoints, including ß-selection, regulatory T-cell generation and γδT-cell development, associated with increased susceptibility to colon and kidney inflammation and infection. We further demonstrated that a single N-glycan antenna (modeled in Rag1Mgat2 mice) is the sine-qua-non condition to ensure normal development. In conclusion, we revealed that mannosylated thymocytes lead to a dysregulation in T-cell development that is associated with inflammation susceptibility.
Topics: Mice; Animals; Humans; Glycosylation; Thymocytes; Thymus Gland; Receptors, Antigen, T-Cell; Homeodomain Proteins; Polysaccharides
PubMed: 37344746
DOI: 10.1038/s41423-023-01052-7 -
The Journal of Physical Chemistry... Nov 2023All protein simulations are conducted with varying degrees of simplification, oftentimes with unknown ramifications about how these simplifications affect the...
All protein simulations are conducted with varying degrees of simplification, oftentimes with unknown ramifications about how these simplifications affect the interpretability of the results. In this work, we investigated how protein glycosylation and lateral crowding effects modulate an array of properties characterizing the stability and dynamics of influenza neuraminidase. We constructed three systems: (1) glycosylated neuraminidase in a whole virion (i.e., crowded membrane) environment, (2) glycosylated neuraminidase in its own lipid bilayer, and (3) unglycosylated neuraminidase in its own lipid bilayer. We saw that glycans tend to stabilize the protein structure and reduce its conformational flexibility while restricting the solvent movement. Conversely, a crowded membrane environment encouraged exploration of the free energy landscape and a large-scale conformational change, while making the protein structure more compact. Understanding these effects informs what factors one must consider in attempting to recapture the desired level of physical accuracy.
Topics: Humans; Influenza, Human; Neuraminidase; Glycosylation; Lipid Bilayers; Viral Proteins
PubMed: 37903229
DOI: 10.1021/acs.jpclett.3c02524 -
Biotechnology Advances Oct 2023This review provides a comprehensive overview of our understanding of the role that glycans play in the formation, loading and release of extracellular vesicles (EVs).... (Review)
Review
This review provides a comprehensive overview of our understanding of the role that glycans play in the formation, loading and release of extracellular vesicles (EVs). The capture of EVs (typically with a size of 100-200 nm) is described, including approaches based on glycan recognition with glycan-based analysis offering highly sensitive detection of EVs. Furthermore, detailed information is provided about the use of EV glycans and glycan processing enzymes as potential biomarkers, therapeutic targets or tools applied for regenerative medicine. The review also provides a short introduction into advanced methods for the characterization of EVs, new insights into the biomolecular corona covering EVs and bioanalytical tools available for glycan analysis.
Topics: Glycosylation; Extracellular Vesicles; Biomarkers; Polysaccharides
PubMed: 37307942
DOI: 10.1016/j.biotechadv.2023.108196 -
The Journal of Biological Chemistry Sep 2023The C-terminal domain of the cellular prion protein (PrP) contains two N-linked glycosylation sites, the occupancy of which impacts disease pathology. In this study, we...
The C-terminal domain of the cellular prion protein (PrP) contains two N-linked glycosylation sites, the occupancy of which impacts disease pathology. In this study, we demonstrate that glycans at these sites are required to maintain an intramolecular interaction with the N-terminal domain, mediated through a previously identified copper-histidine tether, which suppresses the neurotoxic activity of PrP. NMR and electron paramagnetic resonance spectroscopy demonstrate that the glycans refine the structure of the protein's interdomain interaction. Using whole-cell patch-clamp electrophysiology, we further show that cultured cells expressing PrP molecules with mutated glycosylation sites display large, spontaneous inward currents, a correlate of PrP-induced neurotoxicity. Our findings establish a structural basis for the role of N-linked glycans in maintaining a nontoxic, physiological fold of PrP.
PubMed: 37507020
DOI: 10.1016/j.jbc.2023.105101 -
The Journal of Biological Chemistry Feb 2024The mammalian SID-1 transmembrane family members, SIDT1 and SIDT2, are multipass transmembrane proteins that mediate the cellular uptake and intracellular trafficking of...
The mammalian SID-1 transmembrane family members, SIDT1 and SIDT2, are multipass transmembrane proteins that mediate the cellular uptake and intracellular trafficking of nucleic acids, playing important roles in the immune response and tumorigenesis. Previous work has suggested that human SIDT1 and SIDT2 are N-glycosylated, but the precise site-specific N-glycosylation information and its functional contribution remain unclear. In this study, we use high-resolution liquid chromatography tandem mass spectrometry to comprehensively map the N-glycosites and quantify the N-glycosylation profiles of SIDT1 and SIDT2. Further molecular mechanistic probing elucidates the essential role of N-linked glycans in regulating cell surface expression, RNA binding, protein stability, and RNA uptake of SIDT1. Our results provide crucial information about the potential functional impact of N-glycosylation in the regulation of SIDT1-mediated RNA uptake and provide insights into the molecular mechanisms of this promising nucleic acid delivery system with potential implications for therapeutic applications.
Topics: Humans; Biological Transport; Glycosylation; Mammals; Membrane Proteins; Nucleotide Transport Proteins; RNA
PubMed: 38237680
DOI: 10.1016/j.jbc.2024.105654