Binding of cell-penetrating penetratin peptides to plasma membrane vesicles correlates directly with cellular uptake

► Affinity of penetratin variants for plasma membrane vesicles (PMVs) was examined. ► Binding to PMVs is arginine-dependent and correlates with uptake in live cells. ► PMVs have a membrane composition representative of the cells they were derived from. ► The results suggest that membrane affinity is a key property for an efficient CPP.