Fig. 6.
The FOXO1 proteins are lost in lymphomas in CBP knockout mice. Representative immunoblot analyses of Skp2, FOXO1, phosphorylated Akt at Ser-473 (Akt-p), and Akt in normal mouse thymocytes (n = 4), CBP–/– lymphomas (n = 8) (A), or CBP–/–p27KIP1+/– lymphomas (n = 3) (B). Erk2 was used as a loading control. (C) Jurkat cells were transfected with luciferase reporter 3xIRS-Luc and Skp2 siRNAs. At 36 h after transfection, luciferase activity, levels of FOXO1 and Skp2 proteins were analyzed. *, P < 0.05. (D) A diagram depicts the role of Skp2 in tumorigenesis via promoting degradation of FOXO1. Dashed lines indicate the tumor suppression functions of FOXO1 in the absence of interference of Skp2.