Opinion article in Trends in Cell Biology: Plasma membranes: does one model fit all?
In a newly published opinion article in Trends in Cell Biology, Tore Skotland and Kirsten Sandvig in CanCell and the Department of Molecular Cell Biology at the Institute for Cancer Research, discuss the assumptions made to reach the new membrane model.
They conclude that more studies are needed to verify whether the model is true for red blood cells. Moreover, they discuss the large difference in the lipid composition of red blood cells and the plasma membrane of other cells, making it unlikely that one membrane model fits all cell types.
Biological membranes consist of a lipid bilayer with a highly asymmetric distribution of lipids in the two leaflets. It has for many years been assumed that the sum of cholesterol and other lipids is close to being similar in the two leaflets of the plasma membrane, but recent articles in Nature Cell Biology and Cell have challenged this view. The authors of these articles state that there is a 50% overabundance of lipids with two hydrophobic chains in the cytoplasmic leaflet of human red blood cells and that it is compensated by three times more cholesterol in the outer leaflet (60 versus 20 mol%). Moreover, the authors suggest that this is the case also for other cells and that it has been overlooked by the scientific community. If correct, this will have a major effect on our understanding of membrane structure and planning of studies of the plasma membranes of all cells.
Links:
The Trends in Cell Biology article:
Plasma membranes: does one model fit all? (PDF)
Harald Stenmark's group:
Cellular membrane dynamics
Department of Molecular Cell Biology
CanCell - Centre for Cancer Cell Reprogramming (med.uio.no)