GADD153 has been described as a growth arrest and DNA damage-inducible gene that encodes a C/EBP-related nuclear protein. Expression of GADD153 is induced by a variety of cellular stresses, including nutrient deprivation and metabolic perturbations. GADD153 functions to block cells in G1 to S phase in cell cycle progression and acts by dimerizing with other C/EBP proteins to direct GADD153 dimers away from “classical” C/EBP binding sites. Thus GADD153 acts as a negative modulator of C/EBP-like proteins in certain terminally differentiated cells.