AarF Domain Containing Kinase 3 (ADCK3) Mutant Cells Display Signs of Oxidative Stress, Defects in Mitochondrial Homeostasis and Lysosomal Accumulation

PLoS One. 2016 Feb 11;11(2):e0148213. doi: 10.1371/journal.pone.0148213. eCollection 2016.

Abstract

Autosomal recessive ataxias are a clinically diverse group of syndromes that in some cases are caused by mutations in genes with roles in the DNA damage response, transcriptional regulation or mitochondrial function. One of these ataxias, known as Autosomal Recessive Cerebellar Ataxia Type-2 (ARCA-2, also known as SCAR9/COQ10D4; OMIM: #612016), arises due to mutations in the ADCK3 gene. The product of this gene (ADCK3) is an atypical kinase that is thought to play a regulatory role in coenzyme Q10 (CoQ10) biosynthesis. Although much work has been performed on the S. cerevisiae orthologue of ADCK3, the cellular and biochemical role of its mammalian counterpart, and why mutations in this gene lead to human disease is poorly understood. Here, we demonstrate that ADCK3 localises to mitochondrial cristae and is targeted to this organelle via the presence of an N-terminal localisation signal. Consistent with a role in CoQ10 biosynthesis, ADCK3 deficiency decreased cellular CoQ10 content. In addition, endogenous ADCK3 was found to associate in vitro with recombinant Coq3, Coq5, Coq7 and Coq9, components of the CoQ10 biosynthetic machinery. Furthermore, cell lines derived from ARCA-2 patients display signs of oxidative stress, defects in mitochondrial homeostasis and increases in lysosomal content. Together, these data shed light on the possible molecular role of ADCK3 and provide insight into the cellular pathways affected in ARCA-2 patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Survival
  • Cytosol / metabolism
  • DNA Damage
  • Endopeptidase K / metabolism
  • Gene Expression Regulation
  • Glutathione Transferase / metabolism
  • HeLa Cells
  • Homeostasis
  • Humans
  • Lentivirus / genetics
  • Lysosomes / metabolism*
  • Membrane Potential, Mitochondrial
  • Mitochondria / metabolism*
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism*
  • Mutagenesis, Site-Directed
  • Mutation
  • Oxidative Phosphorylation
  • Oxidative Stress*
  • Protein Structure, Tertiary
  • RNA Interference
  • Reactive Oxygen Species / metabolism
  • Recombinant Fusion Proteins / chemistry
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Ubiquinone / analogs & derivatives
  • Ubiquinone / chemistry

Substances

  • COQ8 protein, S cerevisiae
  • COQ8A protein, human
  • Mitochondrial Proteins
  • Reactive Oxygen Species
  • Recombinant Fusion Proteins
  • Saccharomyces cerevisiae Proteins
  • Ubiquinone
  • Glutathione Transferase
  • Endopeptidase K
  • coenzyme Q10

Grant support

This work was supported by the Australian Research Council (ARC Discovery Project Grant DP1092466). See www.arc.gov.au.