LAIR1: Proteins and Enzymes

LAIR1 (leukocyte-associated Ig-like receptor-1; CD305) is a transmembrane collagen-binding protein that is expressed in a differentiation- and activation-dependent manner on  T, B, NK and dendritic cells, monocytes, CD34+ hematopoietic progenitors, most thymocytes, and select granulocyte populations. LAIR1 mediated adhesion to collagens in the extracellular matrix inhibits B and T cell receptor-mediated activation, NK and T cell-mediated cytotoxicity, and basophil degranulation. LAIR1 is reduced or absent on human B cell chronic lymphocytic leukemia (CLL) and some B and dendritic cells in systemic lupus erythematosus (SLE). A soluble form of LAIR1 found in plasma and urine also binds collagen.