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Gudjon Andri Gylfason  


Membrane microdomains (Lipid rafts)

Research over the last two decades has given rise to a new way of how we need to look at biological membranes.  The fluid-mosaic model, which Singer & Nicolson proposed in the early nineties, states that the amphipathic lipids form a bi-layer membrane and proteins are homogeneously distributed.  We now know that the bi-layer particles can organise into domains, often refereed as lipid rafts, DRM (detergent resistant membrane) or microdomains.

These microdomains have normally distinct characteristic, being rich in cholesterol and sphingolipids.  The ability of different protein to associate with these lipid rafts has profound effects on their function, revealing their role in various signal transduction, protein and lipid sorting, viral and bacterial endocytosis. 

Glycosylphosphatidylinositol-anchored proteins (GPI-proteins) have been shown to reside within lipid rafts. Alkaline phosphatase (AP) from animals is a GPI-protein and Atlantic cod AP has been studied for a number of years in our lab. However, the isolation and characterization of lipid rafts is a new approach for our laboratory.