Humanin: The First Mitochondrial-Derived Peptide

Discovery

Humanin was identified in a screen for factors protecting neurons from a specific insult in culture. Its coding sequence was traced to the mitochondrial 16S rRNA gene, making it the first described member of the mitochondrial-derived peptide family.

Reported mechanisms

The literature describes both intracellular interactions with apoptotic regulators and extracellular signalling through a trimeric receptor complex. Downstream, reports point to STAT3 signalling and modulation of apoptotic thresholds.

Analogues with amino acid substitutions have been generated to increase potency in cell assays, and much of the published work uses those analogues rather than the native sequence — a detail worth checking before comparing studies.

What has not been established

There are no controlled human administration trials establishing outcomes. Human data are correlational: circulating levels measured across ages and disease states. Correlation with age tells you nothing about what administration would do.