The main goal of the functional assay group is to develop cell-based assays for the pathogenesis of Huntington’s disease (HD). These assays subsequently will be used to elucidate the molecular mechanism of HD and to test small molecules that can modulate htt misfolding and aggregation. Neuronal cells like PC12, N2A and HEK cells are used for systematic investigations. Wild type and mutant huntingtin fragments of various lengths will be systematically expressed in different cell models and protein misfolding, aggregate formation toxicity will be examined. In addition we will establish ELISA assays to systematically monitor polyglutamine-mediated alterations in different signalling pathways. An ELISA assay for the quantification of AKT phosphorylation in mammalian cells is shown in Fig. 1.