Ferritin

Ferritin is the primary intracellular iron-storage protein complex, composed of a light chain (FTL) and a heavy chain (FTH1) that together form a shell capable of sequestering large amounts of iron in a safe, non-reactive form. By keeping free iron sequestered, ferritin protects cells against iron-catalyzed oxidative damage (the Fenton reaction). Ferritin’s stored iron can, however, be released back into the cell — for example through ferritinophagy — making ferritin a key node that determines whether intracellular iron remains safely stored or becomes available to drive iron-dependent processes such as ferroptosis.