Figure 1.

Localization of nephrocytes and functional comparison with mammals. (A) The schematic shows the anatomical position of nephrocytes (green) within the larval body (left) and the adult fly (right). Garland cell nephrocytes localize within a ring around the esophagus and pericardial nephrocytes are found in pairs along the heart tube. (B) The schematic compares the glomerular function of mammals (left) and Drosophila (right). The mammalian glomerular filter is three-layered, consisting of the fenestrated endothelium, basement membrane, and the podocytes that form foot processes. Between these, the slit diaphragm is localized. Filtration occurs from the blood through the filter into the urinary space. In Drosophila, nephrocytes function as individual cells that are clustered. The glomerular filter is bi-layered, lacking the endothelium. Filtration occurs from the larval blood, the hemolymph, being destined for processing in endosomes.