sialylation

Definition

Target type: biologicalprocess

The covalent attachment of sialic acid to a substrate molecule. [GOC:cjm]

Sialylation is a critical post-translational modification that involves the addition of sialic acid, a negatively charged monosaccharide, to terminal positions of glycans on glycoproteins and glycolipids. This process is catalyzed by a family of enzymes called sialyltransferases, which exhibit specificity for both the donor substrate (CMP-sialic acid) and the acceptor substrate (glycan). Sialylation plays a crucial role in a wide range of biological functions, including cell-cell recognition, immune response modulation, inflammation, and development.

The sialylation process begins with the activation of sialic acid by the enzyme CMP-sialic acid synthetase, which converts sialic acid into its nucleotide-activated form, CMP-sialic acid. This activated form serves as the donor substrate for sialyltransferases. Sialyltransferases then utilize CMP-sialic acid to transfer sialic acid to the terminal galactose or N-acetylglucosamine residues of glycans. The specificity of sialyltransferases is determined by the acceptor substrate, which can be a specific glycan structure or a specific protein.

Sialylation plays a key role in cell-cell recognition and signaling by modifying the surface properties of cells. For example, sialic acid residues on glycoproteins and glycolipids can interact with lectins, which are carbohydrate-binding proteins that mediate cell adhesion and signaling. Sialylation also plays a crucial role in the immune response by influencing the interaction of immune cells with their target cells. For example, sialylation can modulate the recognition of antigens by antibodies and the activation of immune cells.

In addition to its role in cell-cell recognition and immune response, sialylation is also involved in a variety of other biological processes, including inflammation, development, and disease. For example, sialylation has been implicated in the development of cancer and in the progression of inflammatory diseases.

Sialylation is a complex and highly regulated process that is essential for proper cell function and development. The precise roles of sialylation in different biological contexts are still being investigated, but it is clear that this modification has a profound impact on cellular physiology.'
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Proteins (2)

Compounds (12)