GADD153 is a small nuclear protein that is capable of dimerizing with transcription factors C/EBP alpha and beta. Once dimerized, this complex inhibits the normal binding and function of C/EBP to classical binding sites. Inversely, the C/EBP GADD153 dimer gains binding activity to other non classical C/EBP stress related targets. Under normal cellular conditions this protein is not expressed in detectable levels, but is highly unregulated during times of cellular/ER stress.