Methods and compositions are provided for reducing aggregation of neurodegenerative proteins associated with neurotoxicity or other proteins. The compounds comprise a first domain or targeting element for binding to the target proteins linked to a second domain or recruiting element that binds to an aggregation inhibiting protein, e.g. a prolyl isomerase. By associating the aggregating forming proteins or neuronal cells under conditions where aggregating proteins are produced with the compound and the aggregation inhibiting protein, aggregation is reduced. The subject agents can be used in assays, investigating the etiology of the neuronal diseases and for prophylaxis and therapy.