Human IRGM regulates autophagy and cell-autonomous immunity functions through mitochondria

Nat Cell Biol. 2010 Dec;12(12):1154-65. doi: 10.1038/ncb2119. Epub 2010 Nov 21.

Abstract

IRGM, a human immunity-related GTPase, confers autophagic defence against intracellular pathogens by an unknown mechanism. Here, we report an unexpected mode of IRGM action. IRGM demonstrated differential affinity for the mitochondrial lipid cardiolipin, translocated to mitochondria, affected mitochondrial fission and induced autophagy. Mitochondrial fission was necessary for autophagic control of intracellular mycobacteria by IRGM. IRGM influenced mitochondrial membrane polarization and cell death. Overexpression of IRGMd, but not IRGMb splice isoforms, caused mitochondrial depolarization and autophagy-independent, but Bax/Bak-dependent, cell death. By acting on mitochondria, IRGM confers autophagic protection or cell death, explaining IRGM action both in defence against tuberculosis and in the damaging inflammation caused by Crohn's disease.

Publication types

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

MeSH terms

  • Animals
  • Autophagy*
  • Cardiolipins / metabolism
  • Cell Line
  • Dynamins
  • GTP Phosphohydrolases / metabolism
  • GTP-Binding Proteins / analysis
  • GTP-Binding Proteins / metabolism*
  • Humans
  • Mice
  • Microtubule-Associated Proteins / metabolism
  • Mitochondria / chemistry
  • Mitochondria / metabolism*
  • Mitochondrial Proteins / metabolism
  • Protein Isoforms / metabolism

Substances

  • Cardiolipins
  • Microtubule-Associated Proteins
  • Mitochondrial Proteins
  • Protein Isoforms
  • GTP Phosphohydrolases
  • GTP-Binding Proteins
  • IRGM protein, human
  • DNM1L protein, human
  • Dynamins