FBXW7-mediated degradation of CCDC6 is impaired by ATM during DNA damage response in lung cancer cells.

CCDC6 is rearranged in approximately 20% of papillary thyroid carcinomas and some lung cancers participating in the formation of PTC1/ret proto-oncogene oncogene. CCDC6 is involved in the cellular response to DNA damage and is stabilized by ATM-mediated phosphorylation at Thr434. However, the E3 ligase that targets CCDC6 for destruction is unknown. Here, we show that FBXW7 interacts with and targets CCDC6 for ubiquitin-mediated proteasomal degradation. Moreover, FBXW7-mediated CCDC6 degradation is impaired in response to DNA damage. Mechanistically, phosphorylation of CCDC6 at Thr434 by ATM during DNA damage response prevents FBXW6-CCDC6 interaction and FBXW7-mediated CCDC6 degradation. Our results suggest that the involvement of FBXW7 in targeting CCDC6 for destruction will be useful for the establishment of new therapeutic approaches for cancer treatment.