Killer Cell lectin-Like Receptor Subfamily K， Member 1 （KLRK1） is an activating receptor which has recently generated considerable interest. The most fascinating of these， are a couple of closely related proteins known as MICA and MICB. These are cell-surface molecules distantly related to MHC class I proteins， and their genes have elements of heat shock promoters. Thus， MICA and MICB are expressed in the course of cell stress and are up-regulated in tumor cells and during viral infections. This receptor-ligand combination has a crucial role in the immune response to various pathologies.
