UBA1 and proximal spinal muscular atrophy: Western blot analyses of a panel of proteins known to be perturbed in SMA mice as a consequence of reduced Uba1 levels (14) revealed a correction in levels of β-catenin as well as restoration of monoubiquitin and polyubiquitin in SMA mice treated with AAV9-UBA1 (Figure 7, A–D).