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Nature Dec 2023Coronavirus spike proteins mediate receptor binding and membrane fusion, making them prime targets for neutralizing antibodies. In the cases of severe acute respiratory...
Coronavirus spike proteins mediate receptor binding and membrane fusion, making them prime targets for neutralizing antibodies. In the cases of severe acute respiratory syndrome coronavirus, severe acute respiratory syndrome coronavirus 2 and Middle East respiratory syndrome coronavirus, spike proteins transition freely between open and closed conformations to balance host cell attachment and immune evasion. Spike opening exposes domain S1, allowing it to bind to proteinaceous receptors, and is also thought to enable protein refolding during membrane fusion. However, with a single exception, the pre-fusion spike proteins of all other coronaviruses studied so far have been observed exclusively in the closed state. This raises the possibility of regulation, with spike proteins more commonly transitioning to open states in response to specific cues, rather than spontaneously. Here, using cryogenic electron microscopy and molecular dynamics simulations, we show that the spike protein of the common cold human coronavirus HKU1 undergoes local and long-range conformational changes after binding a sialoglycan-based primary receptor to domain S1. This binding triggers the transition of S1 domains to the open state through allosteric interdomain crosstalk. Our findings provide detailed insight into coronavirus attachment, with possibilities of dual receptor usage and priming of entry as a means of immune escape.
Topics: Humans; Allosteric Regulation; Betacoronavirus; Common Cold; Cryoelectron Microscopy; Molecular Dynamics Simulation; Polysaccharides; Protein Binding; Protein Conformation; Sialic Acids; Spike Glycoprotein, Coronavirus; Immune Evasion
PubMed: 37794193
DOI: 10.1038/s41586-023-06599-z -
FEBS Letters Oct 2023The nuclear pore complex (NPC) is among the most elaborate protein complexes in eukaryotes. While ribosomes and proteasomes are known to require dedicated assembly... (Review)
Review
The nuclear pore complex (NPC) is among the most elaborate protein complexes in eukaryotes. While ribosomes and proteasomes are known to require dedicated assembly machinery, our understanding of NPC assembly is at a relatively early stage. Defects in NPC assembly or homeostasis are tied to movement disorders, including dystonia and amyotrophic lateral sclerosis (ALS), as well as aging, requiring a better understanding of these processes to enable therapeutic intervention. Here, we discuss recent progress in the understanding of NPC assembly and highlight how related defects in human disorders can shed light on NPC biogenesis. We propose that the condensation of phenylalanine-glycine repeat nucleoporins needs to be carefully controlled during NPC assembly to prevent aberrant condensation, aggregation, or amyloid formation.
PubMed: 37620293
DOI: 10.1002/1873-3468.14725 -
Chemistry and Physics of Lipids Jul 2023Labyrinthopeptins constitute a class of ribosomal synthesized peptides belonging to the type III family of lantibiotics. They exist in different variants and display...
Labyrinthopeptins constitute a class of ribosomal synthesized peptides belonging to the type III family of lantibiotics. They exist in different variants and display broad antiviral activities as well as show antiallodynic activity. Although their mechanism of action is not understood, it has been described that Labyrinthopeptins interact with membrane phospholipids modulating its biophysical properties and point out to membrane destabilization as its main point of action. We have used all-atom molecular dynamics to study the location of labyrinthopeptin A2 in a complex membrane as well as the existence of specific interactions with membrane lipids. Our results indicate that labyrinthopeptin A2, maintaining its globular structure, tends to be placed at the membrane interface, mainly between the phosphate atoms of the phospholipids and the oxygen atom of cholesterol modulating the biophysical properties of the membrane lipids. Outstandingly, we have found that labyrinthopeptin A2 tends to be preferentially surrounded by sphingomyelin while excluding cholesterol. The bioactive properties of labyrinthopeptin A2 could be attributed to the specific disorganization of raft domains in the membrane and the concomitant disruption of the overall membrane organization. These results support the improvement of Labyrinthopeptins as therapeutic molecules, opening up new opportunities for future medical advances.
Topics: Membrane Lipids; Phospholipids; Bacteriocins; Cholesterol; Membrane Microdomains
PubMed: 37061155
DOI: 10.1016/j.chemphyslip.2023.105303 -
BioRxiv : the Preprint Server For... Aug 2023Langya virus (LayV) is a recently discovered henipavirus (HNV), isolated from febrile patients in China. HNV entry into host cells is mediated by the attachment (G) and...
Langya virus (LayV) is a recently discovered henipavirus (HNV), isolated from febrile patients in China. HNV entry into host cells is mediated by the attachment (G) and fusion (F) glycoproteins which are the main targets of neutralizing antibodies. We show here that the LayV F and G glycoproteins promote membrane fusion with human, mouse and hamster target cells using a different, yet unknown, receptor than NiV and HeV and that NiV- and HeV-elicited monoclonal and polyclonal antibodies do not cross-react with LayV F and G. We determined cryo-electron microscopy structures of LayV F, in the prefusion and postfusion states, and of LayV G, revealing previously unknown conformational landscapes and their distinct antigenicity relative to NiV and HeV. We computationally designed stabilized LayV G constructs and demonstrate the generalizability of an HNV F prefusion-stabilization strategy. Our data will support the development of vaccines and therapeutics against LayV and closely related HNVs.
PubMed: 37645760
DOI: 10.1101/2023.08.20.554025 -
Antiviral Research Jun 2024Cellular sphingolipids have vital roles in human virus replication and spread as they are exploited by viruses for cell entry, membrane fusion, genome replication,... (Review)
Review
Cellular sphingolipids have vital roles in human virus replication and spread as they are exploited by viruses for cell entry, membrane fusion, genome replication, assembly, budding, and propagation. Intracellular sphingolipid biosynthesis triggers conformational changes in viral receptors and facilitates endosomal escape. However, our current understanding of how sphingolipids precisely regulate viral replication is limited, and further research is required to comprehensively understand the relationships between viral replication and endogenous sphingolipid species. Emerging evidence now suggests that targeting and manipulating sphingolipid metabolism enzymes in host cells is a promising strategy to effectively combat viral infections. Additionally, serum sphingolipid species and concentrations could function as potential serum biomarkers to help monitor viral infection status in different patients. In this work, we comprehensively review the literature to clarify how viruses exploit host sphingolipid metabolism to accommodate viral replication and disrupt host innate immune responses. We also provide valuable insights on the development and use of antiviral drugs in this area.
PubMed: 38908521
DOI: 10.1016/j.antiviral.2024.105942 -
Biomaterials Nov 2023Targeting the activated epidermal growth factor receptor (EGFR) via clustered regularly interspaced short palindromic repeat (CRISPR) technology is appealing to overcome...
Targeting the activated epidermal growth factor receptor (EGFR) via clustered regularly interspaced short palindromic repeat (CRISPR) technology is appealing to overcome the drug resistance of hepatocellular carcinoma (HCC) towards tyrosine kinase inhibitor (TKI) therapy. However, combining these two distinct drugs using traditional liposomes results in a suboptimal synergistic anti-HCC effect due to the limited CRISPR/Cas9 delivery efficiency caused by lysosomal entrapment after endocytosis. Herein, we developed a liver-targeting gene-hybridizing-TKI fusogenic liposome (LIGHTFUL) that can achieve high CRISPR/Cas9 expression to reverse the EGFR-mediated drug resistance for enhanced TKI-based HCC therapy efficiently. Coated with a galactose-modified membrane-fusogenic lipid layer, LIGHTFUL reached the targeting liver site to fuse with HCC tumor cells, directly and efficiently transporting interior CDK5- and PLK1-targeting CRISPR/Cas9 plasmids (pXG333-CPs) into the HCC cell cytoplasm and then the cell nucleus for efficient expression. Such membrane-fusion-mediated pXG333-CP delivery resulted in effective downregulation of both CDK5 and PLK1, sufficiently inactivating EGFR to improve the anti-HCC effects of the co-delivered TKI, lenvatinib. This membrane-fusion-participant codelivery strategy optimized the synergetic effect of CRISPR/Cas9 and TKI combinational therapy as indicated by the 0.35 combination index in vitro and the dramatic reduction of subcutaneous and orthotopic TKI-insensitive HCC tumor growth in mice. Therefore, the established LIGHTFUL provides a unique co-delivery platform to combine gene editing and TKI therapies for enhanced synergetic therapy.
Topics: Animals; Humans; Mice; Carcinoma, Hepatocellular; Cell Line, Tumor; Drug Resistance, Neoplasm; ErbB Receptors; Liver Neoplasms; Nanomedicine; Tyrosine
PubMed: 37844429
DOI: 10.1016/j.biomaterials.2023.122349 -
Cell Reports Nov 2023Maintaining cellular viability relies on the integrity of the plasma membrane, which must be repaired upon damage. Soluble N-ethylmaleimide-sensitive factor attachment...
Maintaining cellular viability relies on the integrity of the plasma membrane, which must be repaired upon damage. Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-mediated membrane fusion is a crucial mechanism involved in membrane repair. In C. elegans epidermal cell hyp 7, syntaxin-2 (SYX-2) facilitates large membrane wound repair; however, the underlying molecular mechanism remains unclear. Here, we found that SNAP-25 protein RIC-4 and synaptobrevin protein SEC-22 are required for SYX-2 recruitment at the wound site. They interact to form a SNARE complex to promote membrane repair in vivo and fusion in vitro. Moreover, we found that SEC-22 localized in multiple intracellular compartments, including endosomes and the trans-Golgi network, which recruited to the wounds. Furthermore, inhibition of RAB-5 disrupted SEC-22 localization and prevented its interaction with SYX-2. Our findings suggest that RAB-5 facilitates the formation of the RIC-4/SEC-22/SYX-2 SNARE complex and provides valuable insights into the molecular mechanism of how cells repair large membrane wounds.
Topics: Animals; Syntaxin 1; Caenorhabditis elegans; SNARE Proteins; Cell Membrane; Wound Healing; Qa-SNARE Proteins
PubMed: 37910502
DOI: 10.1016/j.celrep.2023.113349 -
Journal of Cell Science Jul 2023Neuronal dense-core vesicles (DCVs) contain neuropeptides and much larger proteins that affect synaptic growth and plasticity. Rather than using full collapse exocytosis...
Neuronal dense-core vesicles (DCVs) contain neuropeptides and much larger proteins that affect synaptic growth and plasticity. Rather than using full collapse exocytosis that commonly mediates peptide hormone release by endocrine cells, DCVs at the Drosophila neuromuscular junction release their contents via fusion pores formed by kiss-and-run exocytosis. Here, we used fluorogen-activating protein (FAP) imaging to reveal the permeability range of synaptic DCV fusion pores and then show that this constraint is circumvented by cAMP-induced extra fusions with dilating pores that result in DCV emptying. These Ca2+-independent full fusions require PKA-R2, a PKA phosphorylation site on Complexin and the acute presynaptic function of Rugose, the homolog of mammalian neurobeachin, a PKA-R2 anchor implicated in learning and autism. Therefore, localized Ca2+-independent cAMP signaling opens dilating fusion pores to release large cargoes that cannot pass through the narrower fusion pores that mediate spontaneous and activity-dependent neuropeptide release. These results imply that the fusion pore is a variable filter that differentially sets the composition of proteins released at the synapse by independent exocytosis triggers responsible for routine peptidergic transmission (Ca2+) and synaptic development (cAMP).
Topics: Animals; Synaptic Vesicles; Calcium; Synapses; Drosophila; Drosophila Proteins; Synaptic Transmission; Neuropeptides; Exocytosis; Membrane Fusion; Mammals
PubMed: 37303204
DOI: 10.1242/jcs.261026 -
Plants (Basel, Switzerland) Oct 2023Nuclear fusion is essential for the sexual reproduction of various organisms, including plants, animals, and fungi. During the life cycle of flowering plants, nuclear...
Nuclear fusion is essential for the sexual reproduction of various organisms, including plants, animals, and fungi. During the life cycle of flowering plants, nuclear fusion occurs three times: once during female gametogenesis and twice during double fertilization, when two sperm cells fertilize the egg and the central cell. Haploid nuclei migrate in an actin filament-dependent manner to become in close contact and, then, two nuclei fuse. The nuclear fusion process in plant reproduction is achieved through sequential nuclear membrane fusion events. Recent molecular genetic analyses using showed the conservation of nuclear membrane fusion machinery between plants and the budding yeast . These include the heat-shock protein 70 in the endoplasmic reticulum and the conserved nuclear membrane proteins. Analyses of the mutants of these components show that the completion of the sperm nuclear fusion at fertilization is essential for proper embryo and endosperm development.
PubMed: 37896071
DOI: 10.3390/plants12203608 -
Science Advances Oct 2023The clinical potential of miRNA-based liquid biopsy has been largely limited by the heterogeneous sources in plasma and tedious assay processes. Here, we develop a...
The clinical potential of miRNA-based liquid biopsy has been largely limited by the heterogeneous sources in plasma and tedious assay processes. Here, we develop a precise and robust one-pot assay called dual-surface-protein-guided orthogonal recognition of tumor-derived exosomes and in situ profiling of microRNAs (SORTER) to detect tumor-derived exosomal miRNAs and enhance the diagnostic accuracy of prostate cancer (PCa). The SORTER uses two allosteric aptamers against exosomal marker CD63 and tumor marker EpCAM to create an orthogonal labeling barcode and achieve selective sorting of tumor-specific exosome subtypes. Furthermore, the labeled barcode on tumor-derived exosomes initiated targeted membrane fusion with liposome probes to import miRNA detection reagents, enabling in situ sensitive profiling of tumor-derived exosomal miRNAs. With a signature of six miRNAs, SORTER differentiated PCa and benign prostatic hyperplasia with an accuracy of 100%. Notably, the diagnostic accuracy reached 90.6% in the classification of metastatic and nonmetastatic PCa. We envision that the SORTER will promote the clinical adaptability of miRNA-based liquid biopsy.
Topics: Male; Humans; Exosomes; Membrane Proteins; MicroRNAs; Prostatic Neoplasms; Biomarkers, Tumor
PubMed: 37792944
DOI: 10.1126/sciadv.adi1556