figureposted on 14.04.2011, 00:00 by Gloria Mazock
This image shows the changes that occur in the lipid-storing fat body cells of Drosophila when the abundance of spectrin is reduced. Spectrin is a cytoskeletal protein that forms a lining underneath the plasma membrane of cells. One of the functions of spectrin is to promote the formation of specialized membrane domains by stabilizing membrane proteins in the correct location. By using confocal microscopy to capture images at different focal planes, I was able to begin to characterize the changes that occur in these cells. The green panels show the localization of a plasma membrane marker, Cd8-GFP. The red panels show the localization of a cytoplasmic protein, DS Red. Wild-type fat body cells have a highly invaginated plasma membrane (images on the left). These membrane invaginations envelop a class of small lipid droplets, shown as regions of negative staining. When cells express dsRNA against spectrin, the plasma membrane invaginations are strikingly reduced, as are the class of small cortical lipid droplets (images on the right). These images suggest a model where spectrin plays a role in the formation or maintenance of specialized membrane domains, perhaps by stabilizing the interacting proteins that play a role in the formation or processing of a specialized class of lipid droplets.