Abstract
Lymphocyte activation gene (LAG)-3 (CD223) is a CD4-related activation-induced cell surface molecule that binds to MHC class II molecules with high affinity and negatively regulates T cell expansion and homeostasis. In this study, we show that LAG-3 inhibits CD4-dependent, but not CD4-independent, T cell function via its cytoplasmic domain. Although high affinity interaction with MHC class II molecules is essential for LAG-3 function, tailless LAG-3 does not compete with CD4 for ligand binding. A single lysine residue (K468) within a conserved "KIEELE" motif is essential for interaction with downstream signaling molecules. These data provide insight into the mechanism of action of this important T cell regulatory molecule.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Amino Acid Motifs
-
Amino Acid Sequence
-
Animals
-
Antigens, CD*
-
CD4 Antigens / physiology
-
Conserved Sequence
-
Cytoplasm / immunology
-
Down-Regulation / immunology*
-
Histocompatibility Antigens Class II / immunology
-
Histocompatibility Antigens Class II / metabolism
-
Humans
-
Hybridomas
-
Ligands
-
Lymphocyte Activation / immunology*
-
Lymphocyte Activation Gene 3 Protein
-
Membrane Proteins / chemistry
-
Membrane Proteins / immunology
-
Membrane Proteins / metabolism
-
Membrane Proteins / physiology*
-
Mice
-
Molecular Sequence Data
-
Protein Structure, Tertiary
-
Tumor Cells, Cultured
Substances
-
Antigens, CD
-
CD4 Antigens
-
Histocompatibility Antigens Class II
-
Ligands
-
Membrane Proteins
-
Lymphocyte Activation Gene 3 Protein