The role of autophagy and Alfy in degradation of protein aggregates associated with neurodegenerative disease

Protein conformational disorders are associated with the accumulation of insoluble ubiquitin-containing protein aggregates in the central nervous system (CNS). The traditional view is that such aggregates are degraded by proteasomes, but recent evidence i mplicates autophagy in this process as well. Autophagy is a dynamic process in which cytoplasmic material is sequestered within double membrane-enclosed vesicles, which eventually fuse with lysosomes where the encapsulated material is degraded. We have re cently identified a novel PI(3)P-binding human FYVE domain-containing protein, named Alfy (autophagy linked FYVE protein). Upon amino acid and serum starvation, Alfy re-localizes from the nucleus to filamentous cytoplasmic structures located in close prox imity to autophagic membranes and ubiquitin-containing protein aggregates. Mutations in the Drosophila melanogaster Alfy homologue, blue cheese (bchs), results in a reduced lifespan, due to age-dependent formation of ubiquitin-positive protein aggregates in the CNS and extensive neuronal apoptosis. The fact that bchs mutant flies accumulate protein aggregates is consistent with the idea that Alfy is a regulator of a degradative pathway such as autophagy. Thus, Alfy may serve to target cytosolic protein ag gregates for autophagic degradation. The main goal of this project is to investigate the role of autophagy in general and Alfy in particular for the degradation of protein aggregates associated with neurodegenerative diseases. To achieve this goal we will use Drosophila as a model system, which possesses powerful genetic tools, several available mutants, as well as an array of markers. We will also make Alfy knock out mice and use various proteomics approaches to shed light on the function of Alfy. If our working hypothesis proves to be right, Alfy would be the first molecular link between autophagy and neurodegenerative diseases. I will work for 1 year in Dr. Kim Finley’s lab, Salk Institute, CA, from July 2004.b