scholarly journals Siglec Ligands

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1260
Author(s):  
Anabel Gonzalez-Gil ◽  
Ronald L. Schnaar
Keyword(s):  
Immune System ◽  
Sialic Acid ◽  
Therapeutic Intervention ◽  
Binding Proteins ◽  
Cellular Responses ◽  
Cell Physiology ◽  
Molecular Pathways ◽  
Cell Surfaces ◽  
Sugar Moiety ◽  
Sialic Acid Binding

A dense and diverse array of glycans on glycoproteins and glycolipids decorate all cell surfaces. In vertebrates, many of these carry sialic acid, in a variety of linkages and glycan contexts, as their outermost sugar moiety. Among their functions, glycans engage complementary glycan binding proteins (lectins) to regulate cell physiology. Among the glycan binding proteins are the Siglecs, sialic acid binding immunoglobulin-like lectins. In humans, there are 14 Siglecs, most of which are expressed on overlapping subsets of immune system cells. Each Siglec engages distinct, endogenous sialylated glycans that initiate signaling programs and regulate cellular responses. Here, we explore the emerging science of Siglec ligands, including endogenous sialoglycoproteins and glycolipids and synthetic sialomimetics. Knowledge in this field promises to reveal new molecular pathways controlling cell physiology and new opportunities for therapeutic intervention.

Modulation of sialic acid-binding proteins of rat uterus in response to changing hormonal milieu

1993 ◽  
Vol 126 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Indrani Chakraborty ◽  
Chhabinath Mandal ◽  
Mridula Chowdhury
Keyword(s):  
Sialic Acid ◽  
Binding Proteins ◽  
Rat Uterus ◽  
Sialic Acid Binding ◽  
Hormonal Milieu

scholarly journals Siglec-7 Undergoes a Major Conformational Change When Complexed with the α(2,8)-Disialylganglioside GT1b

2006 ◽  
Vol 281 (43) ◽  
pp. 32774-32783 ◽  
Author(s):  
Helen Attrill ◽  
Akihiro Imamura ◽  
Ritu S. Sharma ◽  
Makoto Kiso ◽  
Paul R. Crocker ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Immune System ◽  
Sialic Acid ◽  
Binding Site ◽  
Structural Data ◽  
Site Structure ◽  
Sialic Acid Binding ◽  
Structural Template ◽  
Polar Interactions ◽  
Ganglioside Gt1b

The siglecs are a group of mammalian sialic acid binding receptors expressed predominantly in the immune system. The CD33-related siglecs show complex recognition patterns for sialylated glycans. Siglec-7 shows a preference for α(2,8)-disialylated ligands and provides a structural template for studying the key interactions that drive this selectivity. We have co-crystallized Siglec-7 with a synthetic oligosaccharide corresponding to the α(2,8)-disialylated ganglioside GT1b. The crystal structure of the complex offers a first glimpse into how this important family of lectins binds the structurally diverse gangliosides. The structure reveals that the C-C′ loop, a region implicated in previous studies as driving siglec specificity, undergoes a dramatic conformational shift, allowing it to interact with the underlying neutral glycan core of the ganglioside. The structural data in combination with mutagenesis studies show that binding of the ganglioside is driven by extensive hydrophobic contacts together with key polar interactions and that the binding site structure is complementary to preferred solution conformations of GT1b.

Siglecs as Immune Cell Checkpoints in Disease

2020 ◽  
Vol 38 (1) ◽  
pp. 365-395 ◽  
Author(s):  
Shiteng Duan ◽  
James C. Paulson
Keyword(s):  
Immune System ◽  
Sialic Acid ◽  
Cell Signaling ◽  
Blood Cells ◽  
Immune Cell ◽  
White Blood Cells ◽  
Therapeutic Interventions ◽  
Cell Type ◽  
Cell Responses ◽  
Sialic Acid Binding

Sialic acid–binding immunoglobulin-type lectins (Siglecs) are expressed on the majority of white blood cells of the immune system and play critical roles in immune cell signaling. Through recognition of sialic acid–containing glycans as ligands, they help the immune system distinguish between self and nonself. Because of their restricted cell type expression and roles as checkpoints in immune cell responses in human diseases such as cancer, asthma, allergy, neurodegeneration, and autoimmune diseases they have gained attention as targets for therapeutic interventions. In this review we describe the Siglec family, its roles in regulation of immune cell signaling, current efforts to define its roles in disease processes, and approaches to target Siglecs for treatment of human disease.

Lectin binding on surfaces of Frankia strains

1983 ◽  
Vol 61 (11) ◽  
pp. 2889-2897 ◽  
Author(s):  
Annie Chaboud ◽  
Maurice Lalonde
Keyword(s):  
Sialic Acid ◽  
Lectin Binding ◽  
Carbohydrate Binding ◽  
Symbiotic Association ◽  
Cell Surfaces ◽  
Species Definition ◽  
Sialic Acid Binding ◽  
Host Plant Specificity ◽  
Binding Lectin

As a prerequisite for the formation of symbiotic association the two partners must come in contact at their cell surfaces, where the phenomena of specificity and recognition are believed to take place. Therefore, in the case of actinorhizal symbioses, probing of Frankia cell surfaces was investigated with fluorescein-labelled lectins as specific markers for sugar residues. Eleven Frankia isolates grown in vitro and originating from Alnus and Elaeagnus host-plant specificity groups were tested with lectins of different carbohydrate-binding specificities. The N-acetylglucosamine and sialic acid binding lectin groups were able to bind to cell surfaces of both type-N and type-P strains of the Alnus group but not to any Frankia strains of the Elaeagnus group. Sugar residues recognized by these lectin groups on colonies of Frankia strains of the Alnus group were detected on hyphae, vesicles, and sporangia but not on mature spores. The present lectin binding study demonstrates that the use of lectins as bioprobes can be a valid tool in the awaited species definition in the genus Frankia.

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