Nuclear localization and signalling activity of inositol lipids

It has been recently shown that also the nucleus is a site for both synthes is and hydrolysis of the phosphorylated forms of phosphatidylinositol. Amon g the enzymes of the cycle we and others have demonstrated that phospholipa se C specific for inositol lipids (PLC) is one of the main steps of the ino sitol lipid cycle. The PLC family and namely the type raised a noticeable i nterest since, because of their common COOH-terminus, it has been shown a n uclear localisation in addition to that at the plasma membrane, The autonom ous intranuclear inositide cycle is endowed, besides the PLC, with conventi onal lipid kinases and phosphatidylinositol 3 kinase (PI3-kinase) which pla ys an important role in granulocytic differentiation. The combination of mo rphology and molecular biology gave us the opportunity to localise the site s inside the nucleus where the cycle takes place and to understand the phys iological significance of such a subcellular compartmentalisation both duri ng cell growth and differentiation.