PFN1 and amyotrophic lateral sclerosis: Five of the ALS associated proteins changed significantly between iPSCs and motor neurons; three of these ubiquitylated proteins (dynactin 1, cytoplasmic dynein 1 heavy chain 1, and sequestosome 1) were upregulated in motor neurons, and two (profilin 1 and valosin-containing protein) were upregulated in iPSCs compared to the motor neurons.