[Perspective] (TORC)ing up purine biosynthesis

Proliferating cells must coordinate their metabolic activities to meet the bioenergetic and biosynthetic demands of anabolic growth. Rapidly growing cells—such as cancer cells—achieve this in part by rewiring their metabolic pathways to increase flux through specific biosynthetic pathways. A more complex issue is how metabolic enzymes are organized to ensure efficient processing of metabolic intermediates. On pages 728 and 733 of this issue, Ben-Sahra et al. (1) and French et al. (2), reveal