The study shows that the naturally occurring peptide Humanin can stick to two cell‑death proteins (BAX and BID) and force them to clump together into amyloid‑like fibers, changing their shape and stopping them from triggering apoptosis. This is a new way Humanin might protect brain cells, but the work is still at a basic lab level and doesn’t give dosing or real‑world use instructions.

Neurodegenerative diseases often are associated with cellular dysregulation that results in premature cell death or apoptosis. A common example is the accumulation of amyloid plaques that promotes the excessive expression of p38 mitogen-activated protein kinase. The increased abundance of this enzyme leads to mass phosphorylation and activation of a protein from the B-cell lymphoma 2 (BCL-2) family, BAX. BAX is the central regulatory protein for mitochondrial outer membrane permeabilization (MOMP), a poration process that commits cells to apoptosis by releasing death-propagating factors from the mitochondria. Recent reports identify a naturally occurring peptide, Humanin (HN), that could block amyloid-beta-associated neuronal apoptosis by interacting with BCL-2 proteins. We recently showed humanin interaction leads to the amyloid-like fibrillation of BAX and a second BCL-2 family member, BID. We proposed this as a novel anti-apoptotic mechanism that inhibits pro-apoptotic BCL-2 proteins from initiating MOMP by sequestering them into fibrils, a heretofore unprecedented phenomenon that involves refolding globular BCL-2 proteins rapidly into fibrils where they undergo significant alpha-helix to beta-sheet fold-switching. Here we seek to further characterize the fibrillation and fold-switch in conditions that are known to induce amyloid fibrillation.