Phosphoinositide Contributions

Science Signaling  14 Aug 2012:
Vol. 5, Issue 237, pp. ec216
DOI: 10.1126/scisignal.2003497

To study the roles of phosphoinositides in the plasma membrane of mammalian cells, Hammond et al. (see the Perspective by Fairn and Grinstein) engineered phosphatase molecules that could be targeted to the membrane on demand, where they would alter the concentrations of the phospholipids phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2] and phosphatidylinositol 4-phosphate (PI4P). PI4P was thought to provide a major source for the synthesis of PI(4,5)P2, but depletion of PI4P did not have much effect on synthesis of PI(4,5)P2. Instead, PI4P appears to help to establish the negative charge at the membrane and thus promote electrostatic interactions with positively charged amino acids in membrane-associated proteins and influencing function of ion channels.

G. R. V. Hammond, M. J. Fischer, K. E. Anderson, J. Holdich, A. Koteci, T. Balla, R. F. Irvine, PI4P and PI(4,5)P2 are essential but independent lipid determinants of membrane identity. Science 337, 727–730 (2012). [Abstract] [Full Text]

G. D. Fairn, S. Grinstein, Precursor or charge supplier? Science 337, 653–654 (2012). [Abstract] [Full Text]