Ligand for the NKG2D receptor, together with at least ULBP2 and ULBP3. ULBPs activate multiple signaling pathways in primary NK cells, resulting in the production of cytokines and chemokines. Binding of ULBPs ligands to NKG2D induces calcium mobilization and activation of the JAK2, STAT5, ERK and PI3K kinase/Akt signal transduction pathway. In CMV infected cells, interacts with soluble CMV glycoprotein UL16. The interaction with UL16 blocked the interaction with the NKG2D receptor, providing a mechanism by which CMV infected cells might escape the immune system. UL16 also causes ULBP1 to be retained in the ER and cis-Golgi apparatus so that it does not reach the cell surface.

Expressed in T-cells, B-cells, erythroleukemia cell lines and in a wide range of tissues including heart, brain, lung, liver, testis, lymph node, thymus, tonsil and bone marrow. Also found in fetal heart, brain, lung and liver.

Belongs to the MHC class I family.

Cell membrane. Endoplasmic reticulum. Detected intracellularly in the endoplasmic reticulum of CMV-infected fibroblasts.