SKP2 and colorectal carcinoma: We found that depletion of Skp2 significantly increased the FBW7 and Mcl-1 interaction (Fig. 5A), enhanced IR-induced Mcl-1 ubiquitination (Fig. 4D), which was dependent on the E3 ligase FBW7 (Fig. 5E), and ultimately sensitizing CRC cells to radiotherapy both in vitro (Fig. 1) and in vivo (Fig. 6).