Neu5Gc-mediated high-affinity interaction is dispensable for CD22 cis-ligands to regulate B cell signaling.

CD22 (also known as Siglec-2) is an inhibitory receptor expressed in B cells. CD22 specifically recognizes α2,6 sialic acid and interacts with α2,6 sialylated membrane proteins expressed on the same cell (cis-ligands) and those derived from outside of the cell (trans-ligands). Previously, CD22 cis-ligands were shown to regulate the activity of CD22, thereby regulating both BCR ligation-induced signaling and low-level "tonic" signaling in the absence of BCR ligation that regulates the survival and differentiation of B cells.

Chondroitin 6-sulphate is required for neuroplasticity and memory in ageing.

Perineuronal nets (PNNs) are chondroitin sulphate proteoglycan-containing structures on the neuronal surface that have been implicated in the control of neuroplasticity and memory. Age-related reduction of chondroitin 6-sulphates (C6S) leads to PNNs becoming more inhibitory. Here, we investigated whether manipulation of the chondroitin sulphate (CS) composition of the PNNs could restore neuroplasticity and alleviate memory deficits in aged mice.

Author Correction: Evolution of host adaptation in the Salmonella typhoid toxin.

The original version of this Letter has been modified in the abstract and main text to better reflect the distribution of Neu5Ac sialoglycans in humans. Additionally, co-author Lingquan Deng's present address has been further clarified.

Evolution of host adaptation in the Salmonella typhoid toxin.

The evolution of virulence traits is central for the emergence or re-emergence of microbial pathogens and for their adaptation to a specific host . Typhoid toxin is an essential virulence factor of the human-adapted bacterial pathogen Salmonella Typhi , the cause of typhoid fever in humans . Typhoid toxin has a unique AB architecture with two covalently linked enzymatic 'A' subunits, PltA and CdtB, associated with a homopentameric 'B' subunit made up of PltB, which has binding specificity for the N-acetylneuraminic acid (Neu5Ac) sialoglycans prominently present in humans .

Studies on the Detection, Expression, Glycosylation, Dimerization, and Ligand Binding Properties of Mouse Siglec-E.

CD33-related Siglecs are a family of proteins widely expressed on innate immune cells. Binding of sialylated glycans or other ligands triggers signals that inhibit or activate inflammation. Immunomodulation by Siglecs has been extensively studied, but relationships between structure and functions are poorly explored.

Psychosine-triggered endomitosis is modulated by membrane sphingolipids through regulation of phosphoinositide 4,5-bisphosphate production at the cleavage furrow.

Endomitosis is a special type of mitosis in which only cytokinesis-the final step of the cell division cycle-is defective, resulting in polyploid cells. Although endomitosis is biologically important, its regulatory aspects remain elusive. Psychosine, a lysogalactosylceramide, prevents proper cytokinesis when supplemented to proliferating cells.

Host adaptation of a bacterial toxin from the human pathogen Salmonella Typhi.

Salmonella Typhi is an exclusive human pathogen that causes typhoid fever. Typhoid toxin is a S. Typhi virulence factor that can reproduce most of the typhoid fever symptoms in experimental animals.

Remodeling of glycans using glycosyltransferase genes.

Remodeling of glycans on the cell surface is an essential technique to analyze cellular function of lectin-glycan ligand interaction. Here we describe the methods to identify the responsible enzyme (glycosyltransferase) regulating the expression of the glycan of interest and to modulate the glycan expression by overexpressing the glycosyltransferase gene. For the identification of the responsible enzyme, we introduce a new method, CIRES (correlation index-based responsible-enzyme gene screening), that consists of statistical comparison of glycan expression profile obtained by flow cytometry and gene expression profile obtained by DNA microarray.

The ligand-binding domain of Siglec-G is crucial for its selective inhibitory function on B1 cells.

Siglec-G is an inhibitory receptor on B1 cells. Siglec-G-deficient mice show a large B1 cell expansion, owing to higher BCR-induced Ca(2+) signaling and enhanced cellular survival. It was unknown why Siglec-G shows a B1 cell-restricted inhibitory function.

Quantitative transcriptomic profiling of branching in a glycosphingolipid biosynthetic pathway.

Cellular biosynthesis of macromolecules often involves highly branched enzyme pathways, thus cellular regulation of such pathways could be rather difficult. To understand the regulatory mechanism, a systematic approach could be useful. We genetically analyzed a branched biosynthetic pathway for glycosphingolipid (GSL) GM1 using correlation index-based responsible enzyme gene screening (CIRES), a novel quantitative phenotype-genotype correlation analysis.