At a cellular level, life-sustaining activities such as glucose metabolism were thought to be carried out by entirely different proteins from those involved in apoptosis, or cell death. “People in the field always thought glucose metabolism and apoptosis were two independent pathways for the cell,” said Nika Danial, Harvard Medical School research fellow in pathology at the Dana-Farber Cancer Institute. But the line between survival and extinction may be growing more tenuous. Danial, Emily Cheng, Stanley Korsmeyer, and colleagues have discovered that two of the cell’s most notorious death proteins, BAK and BAD, have intimate partnerships with life-sustaining molecules and may help them carry out their survival activities. The findings, reported in two separate papers, could hold clues to new approaches for treating diseases as disparate as hepatitis, diabetes, and certain cancers. In some cases, the goal would be to prolong the lives of cells; in another — that of cancer — to get them to die more quickly.