Leukocytes navigate by compass: roles of PI3K gamma and its lipid products

Morphologic polarity is necessary for the motility of mammalian cells. In l eukocytes responding to a chemoattractant, this Polarity is regulated by ac tivities of small Rho guanosine triphosphatases (Rho GTPases) and the phosp hoinositide 3-kinases (PI3Ks). Moreover, in neutrophils, lipid products of PI3Ks appear to regulate activation of Rho GTPases, are required fur cell m otility and accumulate asymmetrically to the plasma membrame at the leading edge of polarized cells. By spatially regulating Rho GTPases and organizin g the leading edge of the cell, PI3Ks and their lipid products could play p ivotal roles not only in establishing leukocyte polarity but also as compas s molecules that tell the cell where to crawl.