(a) Proteolysis in HEK293 cells stably transfected with an empty plasmid (Ctr) or plasmids expressing WT or G/S LRRK2 under the control of a tet promoter, treated with doxycycline to activate protein expression and then labeled with [3H]leucine for 48 h. After extensive washing, protein degradation at the indicated times was measured, in cells maintained either in the presence (+) or absence (-) of serum, as the amount of acid-precipitable radioactivity (amino acids and small peptides) released into the media. Values are expressed as percentage of radioactivity in proteins (acid precipitable) at time 0 (n = 4 independent experiments, each in triplicate). 