Expression of Rac1 is constant through the cell cycle. (A) Confocal images of asynchronous T98G cells expressing GFP-Rac1 with the percent of the transfected population represented by each pattern indicated. T98G (B) or IMR-90 (C) cells were synchronized by serum deprivation for 72 h and then induced to cycle by refeeding with 10% FBS. Aliquots of cells were harvested at the times indicated and assayed for Rac1 and the indicated control proteins by immunoblotting. Bar, 5 μm.