KLRB1 has an inhibitory role on natural killer （NK） cells cytotoxicity which are lymphocytes who facilitate cytotoxicity and secrete cytokines subsequent to immune stimulation. Some genes of the C-type lectin superfamily， like the rodent NKRP1 family of glycoproteins， are expressed by NK cells and take part in NK cell function regulation. KLRB1 holds an extracellular domain with a few characteristic motifs of C-type lectins， a transmembrane domain， and a cytoplasmic domain. Due to its external C terminus KLRB1 is considered to be a type II membrane protein.
