In contrast, low IU1 concentrations (<sub>L</sub>IU1≤25μM) or USP14 knockdown by siRNA in rat cortical cultures or loss of USP14 in cortical cultures from ataxia (Usp14<sup>axJ</sup>) mice, failed to prevent PGJ2-induced Ub-protein accumulation.
We previously showed that loss of USP14 in ataxia (ax (J)) mice results in reduced ubiquitin levels, motor endplate disease, Purkinje cell axonal dystrophy and decreased hippocampal paired pulse facilitation (PPF) during the first 4-6 weeks of life, and early postnatal lethality by two months of age.