'Unfolding' pathways in neurodegenerative disease.

The endoplasmic reticulum responds to stress by initiating a cascade of events known as the 'unfolded-protein response' (UPR). The accumulation of misfolded proteins in the leukodystrophy Pelizaeus-Merzbacher disease activates this stress response, resulting in apoptosis of oligodendrocytes. Although it remains uncertain whether the UPR plays a mechanistic role in prototypical neurodegenerative disorders such as Alzheimer's disease, this is plausible because misfolded proteins are directly implicated in the pathogenesis of these disorders.