Chemotaxis, the directed migration of cells in chemical gradients, is a vital process in normal
physiology and in the pathogenesis of many diseases. Chemotactic cells display motility,
directional sensing, and polarity. Motility refers to the random extension of pseudopodia,
which may be driven by spontaneous actin waves that propagate through the cytoskeleton.
Directional sensing is mediated by a system that detects temporal and spatial stimuli and
biases motility toward the gradient. Polarity gives cells morphologically and functionally …