Structural basis for sorting mechanism of p62 in selective autophagy

J Biol Chem. 2008 Aug 15;283(33):22847-57. doi: 10.1074/jbc.M802182200. Epub 2008 Jun 4.

Abstract

Impairment of autophagic degradation of the ubiquitin- and LC3-binding protein "p62" leads to the formation of cytoplasmic inclusion bodies. However, little is known about the sorting mechanism of p62 to autophagic degradation. Here we identified a motif of murine p62 consisting of 11 amino acids (Ser334-Ser344) containing conserved acidic and hydrophobic residues across species, as an LC3 recognition sequence (LRS). The crystal structure of the LC3-LRS complex at 1.56 angstroms resolution revealed interaction of Trp340 and Leu343 of p62 with different hydrophobic pockets on the ubiquitin fold of LC3. In vivo analyses demonstrated that p62 mutants lacking LC3 binding ability accumulated without entrapping into autophagosomes in the cytoplasm and subsequently formed ubiquitin-positive inclusion bodies as in autophagy-deficient cells. These results demonstrate that the intracellular level of p62 is tightly regulated by autophagy through the direct interaction of LC3 with p62 and reveal that selective turnover of p62 via autophagy controls inclusion body formation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / chemistry
  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / physiology*
  • Autophagy / physiology*
  • Binding Sites
  • Carrier Proteins / chemistry
  • Carrier Proteins / genetics
  • Lysosomes / physiology
  • Maltose-Binding Proteins
  • Microtubule-Associated Proteins / chemistry
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / physiology
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / metabolism
  • Sequence Deletion
  • Sequestosome-1 Protein
  • Vacuoles / physiology

Substances

  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • LC3 protein, rat
  • Maltose-Binding Proteins
  • Microtubule-Associated Proteins
  • Recombinant Fusion Proteins
  • SQSTM1 protein, human
  • Sequestosome-1 Protein

Associated data

  • PDB/2ZJD