Abstract
The composition of the cell membrane is not homogeneous, and each organelle has its own unique lipid composition. Asymmetric distribution of membrane lipids between bilayers is also known and microdomains with different lipid compositions exist on the same membrane leaflet, such as lipid rafts. These heterogeneous lipid distributions not only affect the physical properties of biological membranes, but are also thought to play various physiological roles by regulating the localization and function of membrane proteins. However, there are only limited tools for analyzing the localization of membrane lipids, and our understanding of membrane lipids is still lagging behind that of proteins. We have examined intracellular and transbilayer distribution of membrane lipids by using quick–freezing and freeze–fracture replica labeling (QF–FRL) electron microscopy. In this review, I summarize our recent findings on the regulating mechanisms of membrane lipid distribution revealed by using QF–FRL.
