CXCR7, an atypical chemokine receptor, is upregulated in enzalutamide-resistant prostate cancer. Activated CXCR7 interacts with β-arrestin 2 and internalizes into endosomes, wherein the complex acts as a scaffold protein for MAPK protein assembly. MAPK signaling provides an alternative survival pathway, leading to enzalutamide resistance. Using immunofluorescence, it was found that ectopically expressed CXCR7 localized mainly in the cytoplasmic aggregates, colocalizing with β-arrestin 2 in the endosomes. For details, see article by Li and colleagues on page 2580.