An exciting new discovery and possibly providing the first example of an organelle knockout is the absence of caveolae after the protein caveolin-1 (cav-1) is genetically prevented from being expressed in transgenic mice. The scientists have characterised the phenotype of transgenic mice that lack caveolin-1 and have found that the mice lack caveolae, the small cave-like invaginations of the plasma membrane of a variety of eukaryotic cells. More than 50 years after the discovery of caveolae their function remains a matter of speculation and controversy. The study provides clues as to the function of these organelles and also provides the first example of the effect of removing a cellular organelle.
Caveolae have been associated with various cellular processes such as transcytosis of solutes through endothelial cells, cholesterol transport, signal transduction and tumor suppression. They have a characteristic flask-shape with a diameter of 50-100 nm and are present on many cell types, including endothelial, smooth muscle cells and fat cells. They represent a form of lipid rafts within the plasma membrane, enriched in cholesterol and glycolipids. Cav-1, a small protein of only 21-22 kDa, is to date the best biochemical marker for caveolae. It is assumed to be the major structural component of the caveolar coat that is seen in electron mi
Contact: Claudia Lorenz