Scientists have discovered new evidence for the existence of membrane rafts in living cells, providing new insights into the composition of cell membranes.
Membrane rafts are thought to be very small regions of the cell membrane that contain a unique arrangement of lipids and proteins. These rafts are thought to be important for localizing specific proteins or other biomolecules on the cell membrane. However, their existence remains controversial, as many of the techniques used to probe the membrane also may disrupt its normal organization.
Online this week in Nature Chemical Biology, Hai-Tao He and colleagues use a newly developed fluorescence technique, to investigate the cell membrane. They discover that the dynamic assembly of lipids known as ‘sphingolipids’ together with cholesterol is necessary for raft formation, and that rafts have a specific influence on downstream biological signalling.
Their observations also suggest that raft formation could be influenced by proteins that were thought to be passively floating on the membrane. This study therefore confirms the importance of rafts but also indicates that current models of raft formation may need revision.