O-linked N-acetylglucosamine (O-GlcNAc) transferase (Ogt) catalyzes O-GlcNAc modification. O-GlcNAcylation is increased after cross-linking of the B-cell receptor (BCR), but the physiological function of this reaction is unknown. Here we show that lack of Ogt in B-cell development not only causes severe defects in the activation of BCR signaling, but also perturbs B-cell homeostasis by enhancing apoptosis of mature B cells, partly as a result of impaired response to B-cell activating factor. O-GlcNAcylation of Lyn at serine 19 is crucial for efficient Lyn activation and Syk interaction in BCR-mediated B-cell activation and expansion. Ogt deficiency in germinal center (GC) B cells also results in enhanced apoptosis of GC B cells and memory B cells in an immune response, consequently causing a reduction of antibody levels. Together, these results demonstrate that B cells rely on O-GlcNAcylation to maintain homeostasis, transduce BCR-mediated activation signals and activate humoral immunity.

Crosslinking of B-cell receptor (BCR) sets off an apoptosis programme, but the underlying pathways remain obscure. Here we decipher the molecular mechanisms bridging B-cell activation and apoptosis mediated by post-translational modification (PTM). We find that O-GlcNAcase inhibition enhances B-cell activation and apoptosis induced by BCR crosslinking. This proteome-scale analysis of the functional interplay between protein O-GlcNAcylation and phosphorylation in stimulated mouse primary B cells identifies 313 O-GlcNAcylation-dependent phosphosites on 224 phosphoproteins. Among these phosphoproteins, temporal regulation of the O-GlcNAcylation and phosphorylation of lymphocyte-specific protein-1 (Lsp1) is a key switch that triggers apoptosis in activated B cells. O-GlcNAcylation at S209 of Lsp1 is a prerequisite for the recruitment of its kinase, PKC-β1, to induce S243 phosphorylation, leading to ERK activation and downregulation of BCL-2 and BCL-xL. Thus, we demonstrate the critical PTM interplay of Lsp1 that transmits signals for initiating apoptosis after BCR ligation.

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The photocatalytic reduction of CO2could be achieved over Cu/S-TiO2under UV and visible light irradiation. S-TiO2was fabricated via calcination of TiO2precursor and thiourea, Cu species were plated on the surface of S-TiO2by electroless plating method. XRD revealed that S-TiO2was anatase phase, UV-Vis absorption spectrum showed an excellent visible light absorption of Cu/S-TiO2. Cu species plated on S-TiO2by electroless plating method could facilitate the photogenerated charges capture, separation and transfer. The products of CO2photocatalytic reduction involved gas phase of methane, carbon monoxide and hydrogen, and liquid phase of methanol, formic acid and acetic acid. The in-situ IR spectra indicated that the OH radical acted as an intermediate participating in the photocatalytic reaction.

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Surface passivation technology provides noble‐metal materials with limited chemical stability, especially under highly acidic condition. To design effective strategy to enhance stability of noble‐metal particles, an understanding of their surface anticorrosion mechanism at the atomic level is desirable by using two‐dimensional (2D) noble‐metal coordination polymer (CP) as an ideal model for their interfacial region. With the protection of 2‐thiobenzimidazole (TBI), we isolated two Ag‐based 2D CPs, {Ag14(TBI)12X2}n (S−X, where S denotes sheet and X=Cl or Br). These compounds exhibited excellent chemical stability upon immersion in various common solvents, boiling water, boiling ethanol, 10 % hydrogen peroxide, concentrated acid (12 M HCl), and concentrated alkali (19 M NaOH). Systematic characterization and DFT analyses demonstrate that the superior stability of S−X was attributed to the hydrophobic organic shell and dynamic proton buffer layer acting as a double protective “shield”.

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