The effects of oxidative stress on parkin and other E3 ligases.
Autosomal recessive mutations within the Parkin gene are associated with degeneration of the substantia nigra and locus coeruleus and an inherited form of Parkinson's disease (PD). As loss-of-function mutations in parkin are responsible for a familial variant of PD, conditions that affect wild-type parkin are likely to be associated with increased risk of idiopathic disease. Previous studies uncovered a unique vulnerability of the parkin protein to dopamine (DA)-induced aggregation and inactivation. In this study, we compared several proteins that share structural elements or ubiquitinating activity with parkin. We report that oxidative stress in several cell lines and primary neurons induces the aggregation of parkin into high molecular weight species, at least a portion of which are self-associated homo-multimers. While parkin was preferentially affected by excess DA, each of the E3 proteins tested were made more insoluble by oxidative stress, and they varied in degree of susceptibility (e.g. parkin > HHARI congruent with CHIP > c-Cbl > E6AP). These conditions of oxidative stress were also associated with decreased parkin E3 ligase activity. Similar to recently conducted studies on alpha-synuclein processing, both macroautophagy and the proteasome participate in parkin degradation, with the proteasome playing the predominant role for normal parkin turnover and macroautophagy being more important in the degradation of aggregated parkin. These data further highlight the selective vulnerability of parkin to DA-induced modifications, demonstrating for the first time the ability of both endogenous and ectopically expressed parkin to transition into an insoluble state in part through self-association and oligomer formation.
LaVoie
Matthew J
MJ
Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA.
Cortese
Giuseppe P
GP
Ostaszewski
Beth L
BL
Schlossmacher
Michael G
MG
D000818:Animals; D002352:Carrier Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D004298:Dopamine / Q000378:metabolism* / Q000633:toxicity; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D002479:Inclusion Bodies / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D046911:Macromolecular Substances / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D010300:Parkinson Disease / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D011108:Polymers / Q000378:metabolism; D050721:Proto-Oncogene Proteins c-cbl / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D051381:Rats; D013378:Substantia Nigra / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D044767:Ubiquitin-Protein Ligases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination / Q000187:drug effects / Q000502:physiology
D002352:Carrier Proteins; D046911:Macromolecular Substances; D011108:Polymers; C471639:UBE3A protein, human; C419193:ARIH1 protein, human; D050721:Proto-Oncogene Proteins c-cbl; C492951:Stub1 protein, mouse; D044767:Ubiquitin-Protein Ligases; C111567:parkin protein; D004298:Dopamine