Parallel phosphatidylinositol 3-kinase (PI3K)-dependent and Src-dependent pathways lead to CXCL8-mediated Rac2 activation and chemotaxis.

ABSTRACT: The requirement for phosphatidylinositol 3-kinase (PI3K) in the establishment of cell polarity and motility in a number of cell types has recently come into question. In this study, we demonstrate that inhibition of PI3K by wortmannin in neutrophil-like differentiated HL60 cells expressing CXCR2 resulted in reduced cell motility but normal chemotaxis in response to a gradient of CXCL8. However, wortmannin inhibition of PI3K did impair the ability of cells to re-orient their polarity and respond quickly to a change in the direction of the CXCL8 gradient. We hypothesized that Src-regulated ELMO-Dock2-Rac2 activation mediates chemotaxis in the absence of PI3K activity. Inhibition of Src with the small molecule inhibitor, PP2, or inhibition of Dock2 by shRNA knockdown confirmed the functional

SUBMITTER: Sai J 

PROVIDER: S-EPMC2546539 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature