Fig. 6. Model of integrin-talin adhesion complexes in terminal branch maintenance. (Top) Branches sprout from wild-type terminal cells (budding and outgrowth) early in development and are stabilized on their targets (maintenance) by integrin-talin adhesion complexes (red dots). Stabilization may be a reversible process to allow redistribution of branches in response to physiological need (remodeling). (Bottom) Terminal branches sprout normally early in development from rhea^-, mys^- or mew^- if^- terminal cells that lack integrin adhesion complexes. However, branches are unstable and their lumens retract into proximal branches as the rest of the branch degenerates (degeneration).