DNA Damage Inducible Transcript 4 (DDIT4)

The 232-amino acid human protein has a calculated molecular mass of 25 kD and shares 90% amino acid conservation with the rat protein. In an in vitro translation assay, both rat and human RTP801 cDNAs gave rise to 35-kD proteins. Northern blot analysis of human tissues detected low-level ubiquitous expression of a 1.8-kb transcript. Lowest expression was in brain, skeletal muscle, and intestine.

The predicted human REDD1 protein is acidic and rich in serine. It has orthologs in mouse, Xenopus, and Drosophila, with strongest evolutionarily sequence conservation at the C terminus. A related human transcript encodes a protein with 50% overall identity to REDD1, which the authors termed REDD2.