The function of ULBP3 (UL16 binding protein 3, Ensembl gene identifier ENSG00000131019) is as follows. Binds and activates the KLRK1/NKG2D receptor, mediating natural killer cell cytotoxicity. {ECO:0000269|PubMed:11491531, ECO:0000269|PubMed:11754823, ECO:0000269|PubMed:11777960}.