PAF-induced MAPK activation is inhibited by wortmannin in neutrophils and macrophages.

In the present study we examined the mechanism by which PAF activates MAPK in native cells such as guinea-pig neutrophils and P388D1 macrophage-like cells. We found that PAF activates MAPK through two distinct pathways. One calcium-dependent pathway that likely involves cPKC, and another calcium-independent but wortmannin-sensitive pathway. Using molecular biological methods we are presently examining whether hetrodimeric (p85/p110) type PI 3-kinase is the actual target of wortmannin involved in PAF mediated activation of MAPK.