Endocytosis modulates the activities of members of a family of receptors known as Frizzled (Fz) proteins, which control canonical β-catenin signaling and the planar cell polarity pathway; however, what determines which of the two pathways is activated is unclear. Evidence now suggests that the guanosine triphosphatase Rab5, a key regulator of endocytosis, binds directly to Fz proteins and that subsequent trafficking steps determine the outcome of Fz signaling.