Alzheimer’s disease (AD), Parkinson’s disease (PD) and Huntington’s disease (HD) are the most common human neurodegenerative diseases. Each features an abnormal accumulation of proteins, but whether the aggregation leads to neuronal death is controversial. HD is caused by a single mutation that increases the number of CAG repeats. Mutant huntingtin (htt) forms intraneuronal inclusion bodies (IBs). ...