Ly-49 receptors or killer cell lectin-like receptor subfamily A (KLRA), are a class of natural killer cell receptor. Ly-49 proteins are a diverse set of C-type lectins that are expressed on NK cells in some mammals, including rodents but not humans. Their primary function is to bind host MHC class I as a mechanism of self/health recognition. Upon binding ligands, most Ly-49 receptors will deliver an inhibitory signal, preventing killing of the target cell. In the case of cancer or virally infected cells, MHC-I will often be downregulated in order to limit cytotoxic T cell mediated killing of the cell, whereby NK cells will lack Ly-49 inhibitory signal and be able to kill infected or cancerous target cells.
The homologous human KLRAP1 gene has been classified as a transcribed pseudogene because all associated transcripts are candidates for nonsense-mediated decay (NMD).
↑Nylenna O, Naper C, Vaage JT, Woon PY, Gauguier D, Dissen E, Ryan JC, Fossum S (January 2005). "The genes and gene organization of the Ly49 region of the rat natural killer cell gene complex". Eur. J. Immunol. 35 (1): 261–72. doi:10.1002/eji.200425429. PMID15593300.
↑Gays F, Aust JG, Reid DM, Falconer J, Toyama-Sorimachi N, Taylor PR, Brooks CG (November 2006). "Ly49B is expressed on multiple subpopulations of myeloid cells". J. Immunol. 177 (9): 5840–51. doi:10.4049/jimmunol.177.9.5840. PMID17056508.