LAIR proteins are related proteins that each contain one Ig-like domain and thus belong to the Ig superfamily. LAIR1 is a type I transmembrane protein with two cytoplasmic ITIM domains that functions as an inhibitory receptor on NK cells, T cells, B cells, monocytes, dendritic cells and most thymocytes. LAIR2 is a secreted protein with 83% amino acid identity to LAIR1 extracellular domain, but lacks the transmembrane and cytoplasmic domains. The function of LAIR2 is not known. Both LAIR1 and LAIR2 have alternately spliced isoforms.