engleski

Phospholipid second messengers in the cell nucleus

The phosporylation and hydrolysis of phospoinositol lipids is a major pathway for the generation of diverse set of second messenger signaling molecules. A phosphatidylinositol-based phosphorylation/hydrolysis cycle has been identified in the plasma membrane which plays a critical role in the activation of several serine/threonine protein kinases, including protein kinase C and protein kinase B. Diverse methodologies, ranging from activity measurements in various nuclear subfractions to electron microscopy, have been used to demonstrate and established that many of the key lipids and enzymes responsible for the metabolism of inositol lipids are resident in the nucleus. PtdIns, PtdIns(4)P, PtdIns(4,5)P_2 and PtdOH are all present in nuclei, as well as corresponding enzyme activities such as phospholipase C which are required to synthesize and metabolize these compounds. Data related to the existance of alternative pathways of inositol phospholipid synthesis, the role of 3-phosphorylated inositol lipids, possible targets of second messengers derived from inositol lipids in the nucleus and lipid compartmentalization and transport will be discussed together with a role these lipids play in cellular proliferation and differentiation.

cell nucleus; phosphoinositol lipids; second messengers; protein kinase C; protein kinase B; phospholipase C

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