Ubiquitination increases parkin activity to promote autophagic α-synuclein clearance

PLoS One. 2013 Dec 26;8(12):e83914. doi: 10.1371/journal.pone.0083914. eCollection 2013.

Abstract

Parkinson's disease (PD) is a movement disorder associated with genetic and age related causes. Although autosomal recessive early onset PD linked to parkin mutations does not exhibit α-Synuclein accumulation, while autosomal dominant and sporadic PD manifest with α-Synuclein inclusions, loss of dopaminergic substantia nigra neurons is a common denominator in PD. Here we show that decreased parkin ubiquitination and loss of parkin stability impair interaction with Beclin-1 and alter α-Synuclein degradation, leading to death of dopaminergic neurons. Tyrosine kinase inhibition increases parkin ubiquitination and interaction with Beclin-1, promoting autophagic α-Synuclein clearance and nigral neuron survival. However, loss of parkin via deletion increases α-Synuclein in the blood compared to the brain, suggesting that functional parkin prevents α-Synuclein release into the blood. These studies demonstrate that parkin ubiquitination affects its protein stability and E3 ligase activity, possibly leading to α-Synuclein sequestration and subsequent clearance.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis Regulatory Proteins / metabolism
  • Autophagy* / drug effects
  • Beclin-1
  • Brain / drug effects
  • Brain / metabolism
  • Cell Line, Tumor
  • Humans
  • Male
  • Membrane Proteins / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Neurons / drug effects
  • Neurons / metabolism
  • Parkinson Disease / metabolism
  • Parkinson Disease / pathology
  • Protein Kinase Inhibitors / pharmacology
  • Rats
  • Ubiquitin-Protein Ligases / metabolism*
  • Ubiquitination* / drug effects
  • alpha-Synuclein / blood
  • alpha-Synuclein / metabolism*

Substances

  • Apoptosis Regulatory Proteins
  • BECN1 protein, human
  • Beclin-1
  • Membrane Proteins
  • Protein Kinase Inhibitors
  • alpha-Synuclein
  • Ubiquitin-Protein Ligases
  • parkin protein