Stress-induced phospho-ubiquitin formation causes parkin degradation

Lyudmila Kovalchuke; Eugene V. Mosharov; Oren A. Levy; Lloyd A. Greene

The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. It . https://doi.org/10.1101/484857 doi: bioRxiv preprint [103] . However, we did not observe ubiquitination or a significant loss of any of the mitochondrial proteins we evaluated, including VDAC (OMM), Tom20 (OMM), Tim23 (IMM), and UQCRC1 (IMM/matrix), through 48 hours of L-DOPA treatment (Fig. 10A) . To confirm the efficacy of L-DOPA treatment in these experiments, we assessed parkin levels and observed the anticipated decrease (54.1 ± 2.2% loss after 48 hours relative to time zero, p = 0.001 vs. no treatment, N = 3) (Fig. 10A ). In addition, we assessed levels of the long isoform of OPA1, a mitochondrial GTPase that is cleaved in response to mitochondrial stress [104] . L-DOPA treatment induced loss of this isoform (45.0 ± 0.6% decrease after 48 hours relative to time zero, p = 0.01 vs. no treatment, N = 3) (Fig. 10A ), consistent with a promotion of mitochondrial stress.