Figure 1. Regulation of NKG2D ligand expression by mitogens and RAS. Mitogenic signals transactivate various NKG2D ligands and have also been shown to induce the DNA damage response, which stabilizes transcripts coding for NKG2D ligands (NKG2DL) (Hsiung and Raulet, personal communication). RAS-transduced signals increase translation at least in part by stimulating the activity of the rate-limiting translation initiation factor eIF4e.