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