Abstract
EMBO J 30 18, 3714–3728 (2011); published online July 29 2011 A/U-rich elements (AREs) are short sequences in the 3′UTRs of genes, acting in cis to regulate mRNA decay and translation. In this issue of The EMBO Journal, Basu et al (2011) describe a new function for AREs, in the context of the C/EBPβ transcription factor. Specifically, they show that the C/EBPβ ARE is responsible for sequestering the corresponding protein from subcellular compartments in which kinases reside to derepress C/EBPβ. As a result, the transcription factor is unable to execute its cytostatic function in the face of an oncogenic insult. These results reveal a new mode of regulation of an already carefully controlled transcription factor. Given the widespread occurrence of AREs in genes, they also predict that this process, termed ‘3′UTR regulation of protein activity’ (UPA), may have a more common role in controlling protein activities.