Siglec stands for sialic-acid-binding immunoglobulin-like lectins.
Siglecs are a family of transmembrane proteins primarily found on immune cells. Their defining characteristic is their ability to bind to sialic acids, which are sugar molecules commonly found on the surface of cells. This binding capability is mediated by an immunoglobulin-like domain.
Here's a breakdown:
- Sialic acid: A family of acidic monosaccharides (sugar molecules) with a nine-carbon backbone. They are usually found at the outermost ends of glycans (sugar chains) on cell surfaces and in soluble glycoproteins and glycolipids.
- Binding: Refers to the ability of the siglec protein to attach to sialic acid molecules. This interaction is crucial for their function.
- Immunoglobulin-like: Indicates that siglecs possess a structural domain that resembles immunoglobulins (antibodies). This domain is responsible for the sialic acid binding.
- Lectin: A protein that binds carbohydrates. Siglecs are considered lectins because of their sialic acid-binding properties.
Siglecs play a vital role in regulating immune responses through cell-cell interactions and intracellular signaling. They are divided into different subsets based on sequence similarity and evolutionary relationship, reflecting diverse roles in immune regulation.
