PtdIns is a minor membrane phospholipid that is important in signal transduction. Recently, derivatives of PtdIns phosphorylated at the 3-position of the inositol ring have been implicated in the regulation of constitutive membrane traffic and in membrane fusion events. Assembly of the nuclear envelope (NE), a crucial step in the progress of mitosis, is also likely to involve membrane fusion reactions. We therefore investigated the role of PtdIns and phosphoinositide 3-kinase (PI-3K) activity in NE formation in vitro. GTP-induced NE formation was blocked by wortmannin and LY294002, two specific inhibitors of PI-3K, suggesting a role for PtdIns phosphorylated at the 3-position. PtdIns-specific phospholipase C mimicked GTP hydrolysis as an inducer of NE formation. This induction was dependent on a membrane vesicle subfraction (MV1) that was highly enriched in PtdIns, as determined by heteronuclear two-dimensional NMR spectroscopy. On the basis of these results, we suggest that the MV1 population serves as a source of membranes rich in PtdIns that might facilitate fusion, possibly through the production of the membrane-destabilizing lipid diacylglycerol.
Research Article| May 24 2001
Role for phosphatidylinositol in nuclear envelope formation
Banafshé LARIJANI 1
∗Department of Biology, Amherst College, Amherst, MA 01002, U.S.A.
1To whom correspondence should be addressed. Present address: Cell Biophysics Laboratory, Imperial Cancer Research Fund, 44 Lincoln's Inn Fields, London WC2A 3PX, U.K. (e-mail email@example.com).
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Teresa M. BARONA;
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Banafshé LARIJANI, Teresa M. BARONA, Dominic L. POCCIA; Role for phosphatidylinositol in nuclear envelope formation. Biochem J 1 June 2001; 356 (2): 495–501. doi: https://doi.org/10.1042/bj3560495
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