Abstract
p27 is a cyclin-dependent kinase (Cdk) inhibitor and plays an important role in negative regulation of the cell cycle during G0 and G1 phases. Protein level of p27 is controlled by ubiquitin-mediated proteolysis in cell cycle dependent manner. Therefore, degradation of p27 is a critical event for the G1/S transition and occurs through ubiquitination by SCFSkp2 and subsequent degradation by the 26S proteasome. In various types of cancer including oral cancer, down-regulation of p27 is frequently observed. Importantly, down-regulation of p27 is well associated with its malignancy in various cancers. Moreover, It has been revealed that down-regulation of p27 in cancers is due to an enhancement of its degradation. More recent evidence suggests that Skp2 and Cks1, the specific recognition factors for p27 ubiquitination, are involved in down-regulation of p27 in cancer and have oncogenic properties. In the present review, we draw attention to p27 degradation in oral cancer.
