| Budget Amount *help |
¥4,010,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥510,000)
Fiscal Year 2007: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2006: ¥1,800,000 (Direct Cost: ¥1,800,000)
|
|---|
| Research Abstract |
Lateral heterogeneities in the classical fluid-mosaic model of cell membranes are now envisaged as microdomains or 'rafts' that are enriched in gangliosides, cholesterol and specific membrane proteins. The analyses with single-particle tracking and fluorescent resonance energy transfer techniques have suggested that rafts in normal unstimulated cells are extremely small and may last for less than 1 ms. Electron microscopy (EM) would be expected to have sufficient resolving power to visualize rafts if they are in the nanometer size range, but chemical fixatives that need to be used for conventional sample preparations are unlikely to preserve the in situ localization of membrane molecules, particularly lipids, and may even cause artifactual results. Therefore, we used quick-frozen and freeze-fracture replicas which can physically immobilize molecules in situ and thus minimized the possibility of artifactual perturbation. Using this method, the distribution of gangliosides GM1 and GM3, putative raft molecules in the cell membrane, can be visnalized in the nanometer size range, and they show clusters in normal mouse fibroblasts, which are susceptible to cholesterol depletion and chilling (Mol. Biol. Cell, 18, 2112-2122, 2007)
|
