Re-examination of the mechanisms regulating nuclear inositol lipid metabolism

Although inositol lipids constitute only a very minor proportion of total c ellular lipids, they have received immense attention by scientists since it was discovered that they play key roles in a wide range of important cellu lar processes. In the late 1980s, it was suggested that these lipids are al so present within the cell nucleus. Albeit the early reports about the intr anuclear localization of phosphoinositides were met by skepticism and disbe lief, compelling evidence has subsequently been accumulated convincingly sh owing that a phosphoinositide cycle is present at the nuclear level and may be activated in response to stimuli that do not activate the inositol lipi d metabolism localized at the plasma membrane. Very recently, intriguing ne w data have highlighted that some of the mechanisms regulating nuclear inos itol lipid metabolism differ in a substantial way from those operating at t he cell periphery. Here, we provide an overview of recent findings regardin g the regulation of both nuclear phosphatidylinositol 3-kinase and phosphoi nositide-specific phospholipase C-beta1. (C) 2001 Federation of European Bi ochemical Societies. Published by Elsevier Science B.V. All rights reserved .