Before revision: There appear to be mechanisms by which an external chemotactic gradient is sensed and turned into an intracellular PIP3 gradient , which results in a gradient and the activation of a signaling pathway, culminating in the polymerisation of actin filaments.
After revision: There appear to be mechanisms by which an external chemotactic gradientsRas and is sensed and turned into an intracellular PIP3 gradient , which results in a gradient and the activation of a signaling pathway, culminating in the polymerisation of actin filaments.