Retinoic acid early transcript 1G (RAET1G)

Retinoic acid early transcript 1G (**RAET1G**, also known as **ULBP5**) is a non-classical MHC class I-related cell surface glycoprotein encoded by the RAET1G gene on chromosome 6[1][4][8]. Unlike classical MHC molecules, it does not present peptides but instead serves as a stress-induced ligand for the NKG2D receptor on natural killer (NK) cells[1][6][4]. This interaction stimulates NK cell-mediated cytotoxicity against target cells, particularly those that are virally infected or transformed (cancerous)[4][6][1]. RAET1G is primarily expressed in epithelial tissues such as the colon and is upregulated in several tumor cell lines and by cellular stress[4][7]. There are both membrane-bound and soluble isoforms of the protein[4]. RAET1G and related family members are considered important for immune surveillance against tumors and infections, but as of now, no approved therapeutic agents target RAET1G directly. Its main clinical and research significance lies in immunology and oncology, as a signal for immune cell activation in response to cellular distress[1][4][6].

Other names

ULBP5Retinoic acid early transcript 1G proteinRAET1G

Ligand binding to NKG2D receptor on NK cells, triggering immune cell cytotoxicity against stressed or transformed cells (including virally infected or tumor cells)