UL16 binding protein 1 (ULBP1) is a cell surface
glycoprotein
Glycoproteins are proteins which contain oligosaccharide (sugar) chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known a ...
encoded by ''ULBP1'' gene located on the chromosome 6.
ULBP1 is related to
MHC class I
MHC class I molecules are one of two primary classes of major histocompatibility complex (MHC) molecules (the other being MHC class II) and are found on the cell surface of all nucleated cells in the bodies of vertebrates. They also occur on ...
molecules, but its gene maps outside the MHC locus.
The domain structure of ULBP1 differs significantly from those of conventional
MHC class I
MHC class I molecules are one of two primary classes of major histocompatibility complex (MHC) molecules (the other being MHC class II) and are found on the cell surface of all nucleated cells in the bodies of vertebrates. They also occur on ...
molecules. It does not contain the α3 domain and the transmembrane segment. ULBP1 is thus composed of only the α1α2 domain which is linked to the cell membrane by the
GPI anchor
Glycosylphosphatidylinositol () or glycophosphatidylinositol (GPI) is a phosphoglyceride that can be attached to the C-terminus of a protein during posttranslational modification. The resulting GPI-anchored proteins play key roles in a wide vari ...
.
It functions as a
stress-induced ligand for
NKG2D
NKG2D is an activating receptor (transmembrane protein) belonging to the NKG2 family of C-type lectin-like receptors. NKG2D is encoded by ''KLRK1'' (killer cell lectin like receptor K1) gene which is located in the NK-gene complex (NKC) situated ...
receptor.
ULBP1 is, for example, upregulated during
HCMV
Human cytomegalovirus (HCMV), also called human herpesvirus 5 (HHV-5), is a species of virus in the genus ''Cytomegalovirus'', which in turn is a member of the viral family known as ''Herpesviridae'' or herpesviruses. It is also commonly call ...
infection.
Binding of HCMV-encoded UL16 glycoprotein to ULBP1 interferes with cell surface localization of ULBP1; this represents another mechanism by which HCMV-infected cells might escape the immune system.
References
Further reading
*
*
*
*
*
*
*
*
{{gene-6-stub