Nuclear phosphoinositide specific phospholipase C (PI-PLC)-ß1: a central intermediary in nuclear lipid-dependent signal transduction

Abstract

Several studies have demonstrated the existence of an autonomous intranuclear phosphoinositide cycle that involves the activation of nuclear PIPLC and the generation of diacylglycerol (DG) within the nucleus. Although several distinct isozymes of PIPLC have been detected in the nucleus, the isoform that has been most consistently highlighted as being nuclear is PI-PLC-ß1. Nuclear PI-PLC-ß1 has been linked with either cell proliferation or differentiation. Remarkably, the activation mechanism of nuclear PI-PLC-ß1 has been shown to be different from its plasma membrane counterpart, being dependent on phosphorylation effected by p44/42 mitogen activated protein (MAP) kinase. In this review, we report the most up-dated findings about nuclear PI-PLC-ß1, such as the localization in nuclear speckles, the activity changes during the cell cycle phases, and the possible involvement in the progression of myelodisplastic syndrome to acute myeloid leukemia.