Binding of “AT4 receptor” ligands to insulin regulated aminopeptidase (IRAP) in intact Chinese hamster ovary cells

► [3H]AL-11 binds with high affinity to catalytically active IRAP in intact cells. ► After binding to IRAP at the surface, [3H]AL-11 is internalized by endocytosis. ► Binding of [3H]AL-11 drops after pretreating the cells with stable Ang IV-analogs. ► Do stable and unstable Ang IV-analogs produce the same in vivo effects?