ULBP4

ULBP4 (UL16-binding protein 4), also known as RAET1E (retinoic acid early transcript 1E), NKG2DL4 (NKG2D ligand 4) and LETAL (lymphocyte effector cell toxicity activating ligand), is a member of the ULBP/RAET1 family. This and ULBP-5/RAET1G protein differ from other RAET1 proteins in that they have type I membrane-spanning sequences at their C termini rather than glycosylphosphatidylinositol anchor sequences. This protein functions as a ligand for NKG2D receptor, which is expressed on the surface of several types of immune cells, and is involved in innate and adaptive immune responses.