Carbohydrate Sulfation As a Mechanism for Fine-Tuning Siglec Ligands.

The immunomodulatory family of Siglecs recognizes sialic acid-containing glycans as "", which is exploited in cancer for immune evasion. The biochemical nature of Siglec ligands remains incompletely understood, with emerging evidence suggesting the importance of carbohydrate sulfation. Here, we investigate how specific sulfate modifications affect Siglec ligands by overexpressing eight carbohydrate sulfotransferases (CHSTs) in five cell lines.

Modulation of Siglec-7 Signaling Via In Situ-Created High-Affinity -Ligands.

Sialic acid-binding immunoglobulin-like lectins, also known as Siglecs, have recently been designated as glyco-immune checkpoints. Through their interactions with sialylated glycan ligands overexpressed on tumor cells, inhibitory Siglecs on innate and adaptive immune cells modulate signaling cascades to restrain anti-tumor immune responses. However, the elucidation of the mechanisms underlying these processes is just beginning.

Genetically encoded multivalent liquid glycan array displayed on M13 bacteriophage.

The central dogma of biology does not allow for the study of glycans using DNA sequencing. We report a liquid glycan array (LiGA) platform comprising a library of DNA 'barcoded' M13 virions that display 30-1,500 copies of glycans per phage. A LiGA is synthesized by acylation of the phage pVIII protein with a dibenzocyclooctyne, followed by ligation of azido-modified glycans.

A versatile soluble siglec scaffold for sensitive and quantitative detection of glycan ligands.

Sialic acid-binding immunoglobulin-type lectins (Siglecs) are immunomodulatory receptors that are regulated by their glycan ligands. The connections between Siglecs and human disease motivate improved methods to detect Siglec ligands. Here, we describe a new versatile set of Siglec-Fc proteins for glycan ligand detection.

Mass Spectrometry-Based Shotgun Glycomics for Discovery of Natural Ligands of Glycan-Binding Proteins.

Glycans attached to lipids and membrane-bound and secreted proteins and peptides mediate many important physiological and pathophysiological processes through interactions with glycan-binding proteins (GBPs). However, uncovering functional glycan ligands is challenging due to the large number of naturally occurring glycan structures, the limited availability of glycans in their purified form, the low affinities of GBP-glycan interactions, and limitations in existing binding assays. This work explores the application of catch-and-release electrospray ionization mass spectrometry (CaR-ESI-MS) for screening libraries of -glycans derived from natural sources.

Erratum: Author Correction: Repression of phagocytosis by human CD33 is not conserved with mouse CD33.

[This corrects the article DOI: 10.1038/s42003-019-0698-6.].

CUPRA-ZYME: An Assay for Measuring Carbohydrate-Active Enzyme Activities, Pathways, and Substrate Specificities.

Carbohydrate-Active enZymes (CAZymes) are involved in the synthesis, degradation, and modification of carbohydrates. They play critical roles in diverse physiological and pathophysiological processes, have important industrial and biotechnological applications, are important drug targets, and represent promising biomarkers for the diagnosis of a variety of diseases. Measurements of their activities, catalytic pathway, and substrate specificities are essential to a comprehensive understanding of the biological functions of CAZymes and exploiting these enzymes for industrial and biomedical applications.

Repression of phagocytosis by human CD33 is not conserved with mouse CD33.

CD33 is an immunomodulatory receptor linked to Alzheimer's disease (AD) susceptibility via regulation of phagocytosis in microglia. Divergent features between human CD33 (hCD33) and murine CD33 (mCD33) include a unique transmembrane lysine in mCD33 and cytoplasmic tyrosine in hCD33. The functional consequences of these differences in restraining phagocytosis remains poorly understood.

A quantitative, high-throughput method identifies protein-glycan interactions via mass spectrometry.

Glycan binding by glycan-binding proteins and processing by carbohydrate-active enzymes is implicated in physiological and pathophysiological processes. Comprehensive mapping of glycan interactions is essential to understanding of glycan-mediated biology and can guide the development of new diagnostics and therapeutics. Here, we introduce the competitive universal proxy receptor assay (CUPRA), which combines electrospray ionization mass spectrometry, competitive binding and heterobifunctional glycan-based ligands to give a quantitative high-throughput method for screening glycan libraries against glycan-binding and glycan-processing proteins.

Hypersialylation in Cancer: Modulation of Inflammation and Therapeutic Opportunities.

Cell surface glycosylation is dynamic and often changes in response to cellular differentiation under physiological or pathophysiological conditions. Altered glycosylation on cancers cells is gaining attention due its wide-spread occurrence across a variety of cancer types and recent studies that have documented functional roles for aberrant glycosylation in driving cancer progression at various stages. One change in glycosylation that can correlate with cancer stage and disease prognosis is hypersialylation.