Jab1 as a mediator of nuclear export and cytoplasmic degradation of p53.

Jun activation domain-binding protein 1 (Jab1) is involved in various cellular mechanisms including development in Drosophila and mouse, cell cycle control and signal transduction pathways. Recent studies also determined that Jab1 functions as a nuclear exporter and inducer of cytoplasmic degradation for several proteins including p53, p27, capsid of West Nile virus, and Smad4/7 proteins. In particular, p53 is shown to bind to and to be exported into the cytoplasm by Jab1, which helps to maintain low levels of p53 under normal conditions. This review was undertaken in an effort to understand the biological significance of the homeostasis of p53 as maintained in the presence of Jab1. Based on our observations, we have provided potential mechanistic hypotheses for the nuclear export of p53 in coordination with Jab1 and the role of other factors in these processes.