Immunoglobulin superfamily

Immunoglobulin superfamily (IgSF) is a large protein superfamily of cell surface and soluble proteins that are involved in the recognition, binding, or adhesion processes of cells. Molecules are categorized as members of this superfamily based on shared structural features with immunoglobulins (also known as antibodies); they all possess a domain known as an immunoglobulin domain or fold.

Structure

Immunoglobulin-like domains are one of the most common protein modules, and are characterized by 70-110 amino-acid residues. They are often involved in interactions, commonly with other Ig domains or with other molecules. The Ig fold consists of a sandwich of two sheets of antiparallel beta strands, stabilized by a disulfide bridge that connects the two sheets.

Function

Members of the IgSF include cell surface antigen receptors, co-receptors and co-stimulatory molecules of the immune system, molecules involved in antigen presentation to lymphocytes, cell adhesion molecules, certain cytokine receptors and intracellular muscle proteins. They are often involved in recognition, binding, or adhesion processes of cells.

Examples

Examples of human proteins containing this domain include:

• CD4
• CD80
• CD86
• NCAM
• MHC class I
• MHC class II

See also

• Immunoglobulin domain
• Immunoglobulin G
• Immunoglobulin A
• Immunoglobulin M
• Immunoglobulin D
• Immunoglobulin E

References

Immunoglobulin superfamily Resources
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