Lymphocyte-activation gene 3

Lymphocyte-activation gene 3 (also known as LAG-3) is a protein that in humans is encoded by the LAG3 gene. LAG-3, which was discovered in 1990, is a protein on the surface of killer T cells and regulatory T cells that plays a crucial role in regulating the immune response.

Structure

LAG-3 is a transmembrane protein that is structurally similar to CD4. It has four extracellular domains (D1-D4). D1 is close to the membrane and has a similar structure to immunoglobulin variable domains, while D2-D4 are similar to immunoglobulin constant domains.

Function

LAG-3 plays a crucial role in the regulation of the immune response. It is involved in the T cell activation process and is thought to act as a negative regulator of T cell proliferation. LAG-3 binds to MHC class II molecules with a higher affinity than CD4, which may contribute to its inhibitory function.

Clinical significance

LAG-3 is being studied as a potential target for immunotherapy in cancer treatment. Inhibitors of LAG-3 are being developed as potential cancer treatments, with some currently in clinical trials. These inhibitors work by blocking the interaction between LAG-3 and MHC class II, thereby enhancing T cell function and the immune response against cancer cells.

See also

• T cell
• MHC class II
• Immunotherapy

External links

• LAG3 gene at NCBI
• LAG-3 protein at UniProt