Figure 1. FTIs induce the accumulation of prelamin B2. (A) The accumulation of preLB2 and preLA are dependent on the dose of FTI. SDS-PAGE and immunoblotting of lysates prepared from BJ-5ta cells treated for 48 h with the indicated concentrations of L-744,832. (B) The accumulation of preLB2 is time dependent. Cells treated with 2.5 μM L-744,832 for the indicated times. (C) The accumulation of preLB2 requires protein synthesis. Simultaneous addition of cycloheximide (10 μM; CHX) and FTI-L744,832 (2.5 μM) for 24 h. (D) Expression of wild type (WT) and a CAAX motif mutant (CVM) of LB2 in HeLa cells. Twenty-four h following transfection, cells were treated for an additional 48 h with 2.5 μM FTI-L744,832. (E) Total cell lysates from BJ-5ta cells treated FTI or vehicle were immunoblotted with a specific antibody to LB2 (LN43).