Differential Effects of UCH-L1 Inhibition on a-Syn Figure 10. Effects of altered UCH-L1 activity on markers of autophagy. Immunoblot analysis for p62 (A) and LC3I and II (B) of hippocampal homogenates from control or LDN-treated non tg and a-syn tg mice. Quantitative analysis of p62 levels in hippocampal homogenates (C). Quantitative analysis of the ratio of LC3II/I levels in hippocampal homogenates (D). ** Indicates a significant difference between untreated non tg and a-syn tg mice, P,0.01. # Indicates a significant difference between control and LDN-treated a-syn tg mice, P,0.05. B103 rat neuronal cells infected with LV-LC3-GFP and LV–control or LV-a-syn were treated with vehicle or LDN and levels of LC3-GFP signal (E–H) or a-syn (J–M were assessed by immunohistochemistry. Quantitative analysis of LC3-GFP signal in cells (I). Quantitative analysis of a-syn immunoreactivity in neuronal cells (N). Representative immunoblot for a-syn, LC3 and actin in rat neuronal cells infected with LV–control or LV-a-syn and treated with vehicle or LDN (O). Analysis of levels of a-syn and LC3 II/I ratio (P–Q). * Indicates a significant difference between vehicle and LDN-treated LV-control infected cells P,0.01. # Indicates a significant difference between vehicle and LDN-treated LV-a-syn infected cells, P,0.05. doi:10.1371/journal.pone.0034713.g010 functional transient effect of a pharmacological inhibitor such as LDN. In our previous study, we demonstrated that pharmacological suppression of UCH-L1 activity led to reduction in mono- ubiquitin levels, which in turn suppressed ubiquitin-dependent protein degradation by the proteasome [17]. Consequently, UCH- L1-dependent perturbation of proteasome activity affected the stability of important synaptic scaffold proteins, PSD-95 and PLoS ONE | www.plosone.org 12 April 2012 | Volume 7 | Issue 4 | e34713