Figure 6.

The Rho GTPase Rac1 Mediates Ligand-Independent Activation of AR by Ca Vav3

A, PC3 cells were transfected with AR, PSA-luc, and Ca Rac 1 or equimolar amounts of the empty vector. Samples were assayed for luciferase activity as described. The means of triplicate samples are plotted as RLU per μg protein ± sem. Significance was determined using a two-tailed Student’s t test and represents differences from empty vector samples (**, P < 0.01). B, PC3 cells were transfected with Rac1-specific siRNA (Rac1 RNAi) or a scrambled (SCR) control siRNA. Lysates were immunoblotted 48 h after transfection for Rac1 and actin. C, PC3 cells were transfected with AR, PSA-luc, Ca Vav3 (or empty vector), and either Rac1-specific siRNA or a scrambled siRNA control. Samples were assayed for luciferase activity as described. Data are plotted as fold induction compared with empty vector ±sem. Significance was determined using a two-tailed Student’s t test (*, P < 0.05). D, PC3 cells were transfected with the empty vector or Ca Vav3. Rac1 activity (Rac1-GTP) was determined by pull down assays. GTP-bound Rac1 was separated from GDP-Rac1 using the binding domain from the Rac1/Cdc42 effector protein p21-activated kinase fused to GST as described in Materials and Methods. EV, Empty vector; RLU, relative light units.