Although the formation of the Drosophila tracheal system is partly understood, little is known about how the terminal branches of this network of epithelial tubes are maintained. Levi, Ghabrial and Krasnow now reveal that integrin-talin adhesion complexes maintain these branches and their luminal organization (see p. ). Tracheal terminal cells form hollow terminal branches, which adhere tightly to target tissues to supply them with oxygen. In a genetic screen, the researchers isolated tendrils mutants, which have fewer than normal terminal tracheal branches that contain multiple, convoluted lumens. This phenotype arises late in development from loss of branches but not their lumens and is caused by mutations in the gene encoding talin, which links integrin cell-adhesion molecules to the cytoskeleton. Terminal cells mutant for Drosophila β-integrins also show the tendrilsphenotype. The researchers conclude that integrin-talin adhesion complexes anchor mature terminal branches to their target tissues and also maintain their luminal organization. Similar complexes, they suggest, may stabilize other tubular networks.
