Nuclear Lipids Recruiting Protein Kinase in Time for Mitosis

The nuclear lipid cycle and how it is regulated are areas of active investigation (see Irvine). The generation of specific lipid species in the nucleus may play a key role in recruiting and activating lipid-dependent enzymes such as members of the protein kinase C (PKC) family. Deacon et al. suggest that the formation of the tetraunsaturated diacylglycerol species, 1-stearoyl, 2-arachidonyl glycerol (SAG), may be a key element for the localization and activation of PKC βII, a classical PKC isoform that is regulated by calcium and diacylgycerol. PKC βII translocated to the nucleus during the G₂ to M phase of the cell cycle and was presumably activated by its association with the membrane. Furthermore, the concentration of SAG was selectively increased in the nuclei of cells at G₂-M. SAG activated PKC βII and PKC α in vitro. Thus, the localized increase in nuclear SAG may be sufficient to recruit and activate specific PKC isoforms during the G₂-M phase of the cell cycle.

R. Irvine, Nuclear lipid signaling. Science's STKE (2000), http://stke.sciencemag.org/cgi/content/full/OC_sigtrans;2000/48/re1 [Abstract] [Full Text]

E. M. Deacon, T. R. Pettitt, P. Webb, T. Cross, H. Chahal, M. J. O. Wakelan, J. M. Lord, Generation of duacylglycerol molecular species through the cell cycle: a role for 1-stearoyl, 2-arachidonyl glycerol in the activation of nuclear protein kinase C-βII at G2/M. J. Cell Sci. 115, 983-989 (2002). [Online Journal]