Nuclear inositol lipid metabolism: More than just second messenger generation?

A distinct polyphosphoinositide cycle is present in the nucleus, and growing evidence suggests its importance in DNA replication, gene transcript ion, and apoptosis. Even though it was initially thought that nuclear inositol lipids would function as a source for second messengers, recent findings strongly indicate that lipids present in the nucleus also fulfil other roles. The scope of this review is to high light the most intriguing advances made in the field over the last few years, such as the possibility that nuclear phosphatidylinositol (4,5) bisphosphate is involved in maintaining chromatin in a transcriptionalIy active conformation, the new emerging roles for intranuclear phosphatidyl inositol (3,4,5) trisphosphate and phosphoinositide 3-kinase, and the evidence which suggests a tight relationship between a decreased level of nuclear phosphoinositide specific phospholipase C-β1 and the evolution of myelodisplastic syndrome into acute myeloid leukemia.