We adopted a proximity labelling approach, BioID, to identify and compare the protein complexes recruited by Rab4a, Rab11a and Rab25 (a Rab11 family member implicated in cancer aggressiveness), revealing statistically robust protein–protein interaction networks of both new and well-characterised cargoes and trafficking machinery in migratory cancer cells. The gene discussed is RAB4A; the disease is cancer.