Figure 2.

G protein β subunit is required for chemoattractant-induced actin polymerization. F-actin formation in suspended cell cultures following addition of: (A) supernatants from bacterial growth medium or (B) 10⁻⁶ M cAMP. Closed triangles, LW20; open circles, LW6. (A) 1- or (B) 4-h starving cells were used. The mean value of triplicate determinations is shown. Similar results were obtained in five independent experiments. For experimental details refer to Materials and Methods. Bacterial-conditioned medium was prepared by clarification of a stationary phase culture of K. aerogenes grown at 22°C. Medium was used as a stimulus at a dilution of 1:100.