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The nuclear envelope (NE) is a permeable barrier that maintains nuclear-cytoplasmic compartmentalization and ensures nuclear function; however, it ruptures in various situations such as mechanical stress and mitosis. Although the protein components for sealing a ruptured NE have been identified, the mechanism by which lipid components are involved in this process remains to be elucidated. Here, we found that an inner nuclear membrane (INM) protein Bqt4 directly interacts with phosphatidic acid (PA) and serves as a platform for NE maintenance in the fission yeast Schizosaccharomyces pombe. The intrinsically disordered region (IDR) of Bqt4, proximal to the transmembrane domain, binds to PA and forms a solid aggregate in vitro. Excessive accumulation of Bqt4 IDR in INM results in membrane overproliferation and lipid droplet formation in the nucleus, leading to centromere dissociation from the NE and chromosome missegregation. Our findings suggest that Bqt4 IDR controls nuclear membrane homeostasis by recruiting PA to the INM, thereby maintaining the structural integrity of the NE. [ABSTRACT FROM AUTHOR]

Endotoxin research in recent years at the molecular level has required chemically synthesized lipid A without contamination by other bioactive components. Total synthesis of Escherichia coli-type lipid A was achieved in the 1980s by the challenging spirits of the scientists at Osaka University, Japan. They clarified the role of lipid A in the immunological activities of endotoxin in collaboration with Japanese and German researchers, based on the friendships that existed between them. This article introduces the great contributions made by three generations of professors, Tetsuo Shiba, Shoichi Kusumoto, and Koichi Fukase, at the Laboratory of Natural Product Chemistry at Osaka University, to the study over four decades of endotoxin. [ABSTRACT FROM AUTHOR]

4-Chlorophenyl ether was utilized as a new protecting group for the hydroxy function. This group was readily introduced to a sugar hydroxy group by using diaryliodonium triflate. Regioselective introduction of this protecting group at the vicinal cis-diol was achieved by using a copper catalyst and diaryliodonium triflate. This protecting group is stable under the Lewis acidic conditions of glycosylation, but it can be readily removed by the initial conversion into the corresponding 4-methoxyphenyl ether with use of a Pd catalyst, followed by oxidation with ammonium cerium (IV) nitrate [(NH4)2Ce(NO3)6] (CAN). [ABSTRACT FROM AUTHOR]

Keywords: Antibodies; Complement-Dependent Cytotoxicity (CDC); Endocytosis; Imaging; N-Glycans EN Antibodies Complement-Dependent Cytotoxicity (CDC) Endocytosis Imaging N-Glycans 1 1 1 07/21/23 20230724 NES 230724 B Antibody dynamics b on membranes, such as endocytosis and clustering, are vital in determining antibody functions. The glycan-antibody conjugate might provide an alternative strategy for enhancing antibody activity. Yoshiyuki Manabe, Kazuya Kabayama, Koichi Fukase et al. proposed a new approach to modulate antibody dynamics and its function. [Extracted from the article]

Antibody Recruiting, Caged Compound, Glycan Antigen, Glycan Engineering, Metabolic Labelling In their Communication (e202303750), Yoshiyuki Manabe, Koichi Fukase et al. report a glycan-display approach that combines metabolic labeling and the glycan-caging strategy for editing cell-surface glycans. Keywords: Antibody Recruiting; Caged Compound; Glycan Antigen; Glycan Engineering; Metabolic Labelling EN Antibody Recruiting Caged Compound Glycan Antigen Glycan Engineering Metabolic Labelling 1 1 1 06/13/23 20230619 NES 230619 B Glycan Engineering b . [Extracted from the article]

ABO blood group antigens are involved in various biological phenomena, including immune responses and infections. We achieved efficient and scalable synthesis of A, B, and H antigens. Using chemical conjugation, synthesized B antigen was displayed on the surface of living cells and its function as an antigen was confirmed by the IgM antibody recognition. Our results indicate that the multivalent interactions induced by cell surface glycan clustering are crucial in this system. The prepared cells displaying the glycan antigen are expected to be a model cell for investigating ABO antigen function. [ABSTRACT FROM AUTHOR]

Endotoxin research in recent years at the molecular level has required chemically synthesized lipid A without contamination by other bioactive components. Total synthesis of Escherichia coli -type lipid A was achieved in the 1980s by the challenging spirits of the scientists at Osaka University, Japan. They clarified the role of lipid A in the immunological activities of endotoxin in collaboration with Japanese and German researchers, based on the friendships that existed between them. This article introduces the great contributions made by three generations of professors, Tetsuo Shiba, Shoichi Kusumoto, and Koichi Fukase, at the Laboratory of Natural Product Chemistry at Osaka University, to the study over four decades of endotoxin.

The Toll-like receptor 4 (TLR4)/myeloid differentiation factor-2 (MD-2) complex is essential for LPS recognition and induces innate immune responses against Gram-negative bacteria. As activation of TLR4/MD-2 is also critical for the induction of adaptive immune responses, TLR4/MD-2 agonists have been developed as vaccine adjuvants, but their efficacy has not yet been ascertained. Here, we demonstrate that a funiculosin (FNC) variant, FNC-RED, and FNC-RED and FNC derivatives are agonists for both murine and human TLR4/MD-2. FNC-RED induced nuclear factor-κB (NF-κB) activation via murine TLR4/MD-2, whereas FNC had no TLR4/MD-2 stimulatory activity. Biacore analysis revealed that FNC-RED binds to murine TLR4/MD-2 but not murine radioprotective 105 (RP105)/myeloid differentiation factor-1 (MD-1), another LPS sensor. FNC-RED induced CD14-independent expressions of pro-inflammatory cytokines and co-stimulatory molecules in murine macrophages and dendritic cells. In contrast, FNC-RED stimulation was reduced in CD14-dependent LPS responses, including dimerization and internalization of TLR4/MD-2 and IFN-β expression. FNC-RED-induced IL-12p40 production from murine dendritic cells was dependent on NF-κB but not MAPK pathway. In addition, fetal bovine serum augmented lipid A-induced NF-κB activation but blocked FNC-RED-mediated responses. Two synthetic phosphate group-containing FNC-RED and FNC derivatives, FNC-RED-P01 and FNC-P01, respectively, activated human TLR4/MD-2, unlike FNC-RED. Finally, computational analysis revealed that this species-specific activation by FNC-REDandFNC-RED-P01resulted from differences in electrostatic surface potentials between murine and human TLR4/MD-2. We conclude that FNC-RED and its synthetic derivative represent a novel category of murine and human TLR4/MD-2 agonist. [ABSTRACT FROM AUTHOR]

Acetobacter pasteurianus is an aerobic Gram-negative rod that is used in the fermentation process used to produce the traditional Japanese black rice vinegar kurozu. Previously, we found that a hydrophobic fraction derived from kurozu stimulates Toll-like receptors to produce cytokines. LPSs, particularly LPS from A. pasteurianus, are strong candidates for the immunostimulatory component of kurozu. The LPS of A. pasteurianus remains stable in acidic conditions during the 2 years of the abovementioned fermentation process. Thus, we hypothesized that its stability results from its structure. In this study, we isolated the LPS produced by A. pasteurianus NBRC 3283 bacterial cells and characterized the structure of its lipid A component. The lipid A moiety was obtained by standard weak acid hydrolysis of the LPS. However, the hydrolysis was incomplete because a certain proportion of the LPS contained acid-stable D-glycero-D-talo-oct-2-ulosonic acid (Ko) residues instead of the acid-labile 3-deoxy-D-manno-oct-2-ulosonic acid residues that are normally found in typical LPS. Even so, we obtained a Ko-substituted lipid A with a novel sugar backbone, α-Man(1- 4)[α-Ko(2-6)]β-GlcN3N(1-6)α-GlcN(1-1)α-GlcA. Its reducing end GlcN(1-1)GlcA bond was also found to be quite acid-stable. Six fatty acids were attached to the backbone. Both the whole LPS and the lipid A moiety induced TNF-α production in murine cells via Toll-like receptor 4, although their activity was weaker than those of Escherichia coli LPS and lipid A. These results suggest that the structurally atypical A. pasteurianus lipid A found in this study remains stable and, hence, retains its immunostimulatory activity during acetic acid fermentation. [ABSTRACT FROM AUTHOR]

The human pathogen Staphylococcus aureus is responsible for many community-acquired and hospital-associated infections and is associated with high mortality. Concern over the emergence of multidrug-resistant strains has renewed interest in the elucidation of host mechanisms that defend against S. aureus infection. We recently demonstrated that human serum mannose-binding lectin binds to S. aureus wall teichoic acid (WTA), a cell wall glycopolymer--a discovery that prompted further screening to identify additional serum proteins that recognize S. aureus cell wall components. In this report, we incubated human serum with 10 different S. aureus mutants and determined that serum amyloid P component (SAP) bound specifically to a WTA-deficient S. aureus ΔtagO mutant, but not to tagO-complemented, WTA-expressing cells. Biochemical characterization revealed that SAP recognizes bacterial peptidoglycan as a ligand and that WTA inhibits this interaction. Although SAP binding to peptidoglycan was not observed to induce complement activation, SAP-bound ΔtagO cells were phagocytosed by human polymorphonuclear leukocytes in an FcγR-dependent manner. These results indicate that SAP functions as a host defense factor, similar to other peptidoglycan recognition proteins and nucleotide-binding oligomerization domain-like receptors. [ABSTRACT FROM AUTHOR]