Ectopic expression of FBXL2 induces the degradation of cyclin D2. (A-B) MLE cells were transfected with control plasmid lacZ or other V5 tagged F-box proteins (L and W families). Cells were collected and cell lysates were analyzed for V5, cyclin D2 and β-actin immunoblotting. (C) Cells were transfected with increasing amounts of V5-tagged FBXL2 plasmid. Cells were collected and cell lysates were analyzed for V5, cyclin D2, and β-actin immunoblotting. (D) Cyclin D2 protein half-life determination after FBXL2 overexpression (top panel), or FBXL2 knockdown using siRNA (middle panel). Bottom panel shows levels of cyclin D2 on immunoblots that were quantified densitometrically and are shown graphically. The data from each panel represent at least n = 2 separate experiments.