Polarization of chemoattractant receptor signaling during neutrophil chemotaxis

Morphologic polarity is necessary for chemotaxis of mammalian cells. As a p robe of intracellular signals responsible for this asymmetry, the pleckstri n homology domain of the AKT protein kinase (or protein kinase B), tagged w ith the green fluorescent protein (PHAKT-GFP), was expressed in neutrophils . Upon exposure of cells to chemoattractant, PHAKT-GFP is recruited selecti vely to membrane at the cell's leading edge, indicating an internal signali ng gradient that is much steeper than that of the chemoattractant. Transloc ation of PHAKT-GFP is inhibited by toxin-B from Clostridium difficile, indi cating that it requires activity of one or more Rho guanosine triphosphatas es.