Identification of interacting partners of Human Mpv17-like protein with a mitigating effect of mitochondrial dysfunction through mtDNA damage

Free Radic Biol Med. 2015 Oct:87:336-45. doi: 10.1016/j.freeradbiomed.2015.07.008. Epub 2015 Jul 10.

Abstract

Human Mpv17-like protein (M-LPH) has been suggested to participate in mitochondrial function. In this study, we investigated the proteins that interact with M-LPH, and identified four: H2A histone family, member X (H2AX), ribosomal protein S14 (RPS14), ribosomal protein S3 (RPS3) and B-cell receptor-associated protein 31 (Bap31). Immunofluorescence and subcellular fractionation studies revealed that M-LPH is localized predominantly in the nucleus, to some extent in a subset of mitochondria, and marginally in the cytosol. Mitochondrial M-LPH appeared as punctate foci, and these were co-localized with a subset of mitochondrial transcription factor A (TFAM) and mtDNA, indicating that M-LPH is localized in or in close proximity to mitochondrial nucleoids. RNAi-mediated knockdown of M-LPH resulted in an increase of mtDNA damage and reduced the expression of mtDNA-encoded genes. A ROS inducer, antimycin A, caused an increase in both the number and size of the mitochondrial M-LPH foci, and these foci were co-localized with two enzymes, DNA polymerase γ (POLG) and DNA ligase III (LIG3), both involved in mtDNA repair. Furthermore, knockdown of M-LPH hampered mitochondrial localization of these enzymes. Taken together, these observations suggest that M-LPH is involved in the maintenance of mtDNA and protects cells from mitochondrial dysfunction.

Keywords: Mitochondrial DNA; Mitochondrial dysfunction; Mpv17 family; Oxidative stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antimycin A / administration & dosage
  • Cell Line
  • DNA Ligase ATP
  • DNA Ligases / genetics
  • DNA Ligases / metabolism
  • DNA Polymerase gamma
  • DNA Repair / genetics*
  • DNA, Mitochondrial / genetics
  • DNA, Mitochondrial / metabolism*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • DNA-Directed DNA Polymerase / genetics
  • DNA-Directed DNA Polymerase / metabolism
  • Gene Expression Regulation / drug effects
  • Histones / genetics
  • Histones / metabolism
  • Humans
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mitochondria / genetics*
  • Mitochondria / metabolism
  • Mitochondria / pathology
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism
  • Poly-ADP-Ribose Binding Proteins
  • Protein Binding
  • Ribosomal Proteins / genetics
  • Ribosomal Proteins / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Xenopus Proteins

Substances

  • BCAP31 protein, human
  • DNA, Mitochondrial
  • DNA-Binding Proteins
  • H2AX protein, human
  • Histones
  • MPV17L protein, human
  • Membrane Proteins
  • Mitochondrial Proteins
  • Poly-ADP-Ribose Binding Proteins
  • RPS14 protein, human
  • RPS3 protein, human
  • Ribosomal Proteins
  • TFAM protein, human
  • Transcription Factors
  • Xenopus Proteins
  • Antimycin A
  • DNA Polymerase gamma
  • DNA-Directed DNA Polymerase
  • POLG protein, human
  • DNA Ligases
  • DNA Ligase ATP
  • DNA ligase III alpha protein, Xenopus
  • LIG3 protein, human