Iron is essential. Our cells need it to produce energy, carry oxygen throughout the body and power countless chemical reactions that sustain life. But this metal has a dark side. When too much of it is left free inside cells, it can trigger destructive reactions that break down DNA, proteins and even cell membranes.

Now, Whitehead Institute Member Ankur Jain, former postdoc Whitney Henry and graduate student Pushkal Sharma have discovered that cells rely on an unexpected protector against this threat: small molecules called polyamines.

The researchers’ detailed findings, published in the journal Cell, reveal that polyamines act like storage lockers for iron, safely holding the metal in a nonreactive state until cells need it.