Scientists knew the PDK1 signaling pathway was active in metastasizing cancer cells, but no one knew why. New research has found for the first time that the PDK1 pathway regulates the formation of a three-protein core complex that facilitates purine biosynthesis. Further work aims to map all the protein complexes and signaling pathways they regulate in cancer cells, which would open doors to new ways of disrupting or even preventing metastasis.