ENDOSOME-LYSOSOMES AND NEURODEGENERATION

A number of the major human and animal neurodegenerative diseases, suc h as Alzheimer's disease and sheep scrapie, are characterised by depos its of amyloid, arising through incomplete breakdown of membrane prote ins. Although our knowledge concerning these diseases is increasing, t hey remain largely untreatable. Recently, attention has focussed on th e mechanisms of production of different types of amyloid and the likel y involvement within cells of acid compartments called endosome-lysoso mes. These organelles may be 'bioreactor' sites for the unfolding and partial degradation of membrane proteins to generate the amyloid mater ials. These subsequently become expelled from the cell, or are release d from dead cells, and accumulate as pathological entities. Common fea tures of the disease processes give new direction to therapeutic inter vention.