3118 Nucleic Acids Research, 2009, Vol. 37, No. 9 Figure 4. CK1d silencing decreases AIB1 protein levels in the presence of E2. (A) MCF7 cells (2 105) were plated in 6-well plates in phenol red-free DMEM containing 10% DSS. Cells were untransfected or transfected with 5 nM CT siRNA or with 5 nM CK1d siRNA for 72 h and treated or not with E2 (100 nM) for 45 min. Cells were harvested, lysed and equal protein amounts were subjected to western blotting using a speciﬁc AIB1 mouse