The autophagy receptor ALLO-1 and the IKKE-1 kinase control clearance of paternal mitochondria in Caenorhabditis elegans

Nat Cell Biol. 2018 Jan;20(1):81-91. doi: 10.1038/s41556-017-0008-9. Epub 2017 Dec 18.

Abstract

In Caenorhabditis elegans embryos, paternally provided organelles, including mitochondria, are eliminated by a process of selective autophagy called allophagy, the mechanism by which mitochondrial DNA is inherited maternally. However, it remains unclear how paternal organelles are recognized and targeted for autophagy. Here, we identified an autophagy receptor for allophagy, ALLO-1. ALLO-1 is essential for autophagosome formation around paternal organelles and directly binds to the worm LC3 homologue LGG-1 through its LC3-interacting region (LIR) motif. After fertilization, ALLO-1 accumulates on the paternal organelles before autophagosome formation, and this localization depends on the ubiquitin modification of the paternal organelles. We also identified IKKE-1, a worm homologue of the TBK1 and IKKε family kinase, as another critical regulator of allophagy. IKKE-1 interacts with ALLO-1, and the IKKE-1-dependent phosphorylation of ALLO-1 is important for paternal organelle clearance. Thus, we propose that ALLO-1 is the allophagy receptor whose function is regulated by IKKE-1-dependent phosphorylation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagosomes
  • Autophagy / genetics*
  • Autophagy-Related Proteins / genetics*
  • Autophagy-Related Proteins / metabolism
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / metabolism
  • Caenorhabditis elegans Proteins / genetics*
  • Caenorhabditis elegans Proteins / metabolism
  • DNA, Mitochondrial / genetics
  • DNA, Mitochondrial / metabolism
  • Embryo, Nonmammalian
  • Female
  • Gene Expression Regulation
  • Inheritance Patterns*
  • Male
  • Microtubule-Associated Proteins / genetics*
  • Microtubule-Associated Proteins / metabolism
  • Mitochondria / metabolism*
  • Phosphorylation
  • Protein Serine-Threonine Kinases / genetics*
  • Protein Serine-Threonine Kinases / metabolism
  • Signal Transduction
  • Ubiquitin / genetics
  • Ubiquitin / metabolism
  • Ubiquitination

Substances

  • Autophagy-Related Proteins
  • Caenorhabditis elegans Proteins
  • DNA, Mitochondrial
  • LGG-1 protein, C elegans
  • Microtubule-Associated Proteins
  • Ubiquitin
  • Protein Serine-Threonine Kinases