The role of phosphoinositide-3-kinase in the control of shape and directional movement of the Physarum polycephalum plasmodium

The effects of wortmannin and LY294002, specific inhibitors of phosphoinositide-3-kinase, on the shape, locomotive behavior, and glucose chemotaxis were studied using the Physarum polycephalum plasmodium, a multinuclear amoeboid cell with the self-oscillatory mode of locomotive behavior. Both inhibitors were shown to cause a reduction in the plasmodium frontal edge and a decrease in the efficiency of mass transfer during migration. They also suppressed the chemotaxis towards glucose and eliminated the characteristic changes in self-oscillatory behavior normally observed in response to the treatment of the whole plasmodium with glucose. The manifestation of these effects depended on the inhibitor concentration, treatment duration, and size of plasmodium. The involvement of phosphoinositide-3-kinase in formation of the frontal edge and control of P. polycephalum plasmodium chemotaxis suggests that the correlation of polar shape and directional movement of amoeboid cells with the distribution of phosphoinositides in the plasma membrane has a universal nature.