NBR1 is dispensable for PARK2-mediated mitophagy regardless of the presence or absence of SQSTM1

Cell Death Dis. 2015 Oct 29;6(10):e1943. doi: 10.1038/cddis.2015.278.

Abstract

Degradation of malfunctional mitochondria by mitophagy is a pivotal component of mitochondrial quality control to maintain cellular homeostasis. Mitochondrial clearance through the PINK1/PARK2 pathway is mediated by autophagic adaptor proteins. Previous studies revealed a significant involvement, but not an absolute requirement for SQSTM1 in PARK2-dependent mitophagy, suggesting that the existence of redundant adaptor proteins may compensate for the loss of SQSTM1. Here we investigated whether NBR1, a functional homolog of SQSTM1, has a role in PARK2-mediated mitophagy, either alone or as a compensatory mechanism. We showed that NBR1 does not appear to be required for mitochondrial clustering following mitochondrial depolarization. Moreover, we demonstrated that deletion of NBR1 alone or in combination with SQSTM1 does not prevent the degradation of damaged mitochondria. Our data suggest that NBR1 is dispensable for PARK2-dependent mitophagy and additional autophagic adaptor proteins, other than NBR1, are responsible for mitochondrial degradation in cells depleted of SQSTM1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism
  • Adaptor Proteins, Signal Transducing / physiology*
  • Animals
  • Carbonyl Cyanide m-Chlorophenyl Hydrazone / pharmacology
  • Cells, Cultured
  • Gene Deletion
  • HeLa Cells
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Mitophagy / drug effects
  • Mitophagy / genetics*
  • Proteins / genetics
  • Proteins / metabolism
  • Proteins / physiology*
  • Sequestosome-1 Protein
  • Ubiquitin-Protein Ligases / genetics
  • Ubiquitin-Protein Ligases / metabolism
  • Ubiquitin-Protein Ligases / physiology*

Substances

  • Adaptor Proteins, Signal Transducing
  • Intracellular Signaling Peptides and Proteins
  • NBR1 protein, human
  • Proteins
  • SQSTM1 protein, human
  • Sequestosome-1 Protein
  • Carbonyl Cyanide m-Chlorophenyl Hydrazone
  • Ubiquitin-Protein Ligases
  • parkin protein