Sequestosome-1/p62 is the key intracellular target of innate defense regulator peptide

J Biol Chem. 2009 Dec 25;284(52):36007-11. doi: 10.1074/jbc.C109.073627. Epub 2009 Oct 22.


Innate defense regulator-1 (IDR-1) is a synthetic peptide with no antimicrobial activity that enhances microbial infection control while suppressing inflammation. Previously, the effects of IDR-1 were postulated to impact several regulatory pathways including mitogen-activated protein kinase (MAPK) p38 and CCAAT-enhancer-binding protein, but how this was mediated was unknown. Using a combined stable isotope labeling by amino acids in cell culture-proteomics methodology, we identified the cytoplasmic scaffold protein p62 as the molecular target of IDR-1. Direct IDR-1 binding to p62 was confirmed by several biochemical binding experiments, and the p62 ZZ-type zinc finger domain was identified as the IDR-1 binding site. Co-immunoprecipitation analysis of p62 molecular complexes demonstrated that IDR-1 enhanced the tumor necrosis factor alpha-induced p62 receptor-interacting protein 1 (RIP1) complex formation but did not affect tumor necrosis factor alpha-induced p62-protein kinase zeta complex formation. In addition, IDR-1 induced p38 MAPK activity in a p62-dependent manner and increased CCAAT-enhancer-binding protein beta activity, whereas NF-kappaB activity was unaffected. Collectively, these results demonstrate that IDR-1 binding to p62 specifically affects protein-protein interactions and subsequent downstream events. Our results implicate p62 in the molecular mechanisms governing innate immunity and identify p62 as a potential therapeutic target in both infectious and inflammatory diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / immunology*
  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • Binding Sites / genetics
  • Binding Sites / immunology
  • CCAAT-Enhancer-Binding Proteins / immunology
  • CCAAT-Enhancer-Binding Proteins / metabolism
  • Heat-Shock Proteins / genetics
  • Heat-Shock Proteins / immunology*
  • Heat-Shock Proteins / metabolism
  • Humans
  • Immunity, Innate / drug effects*
  • Immunity, Innate / genetics
  • Immunologic Factors / pharmacology*
  • Inflammation / drug therapy
  • Inflammation / genetics
  • Inflammation / immunology
  • Inflammation / metabolism
  • MAP Kinase Signaling System / drug effects*
  • Mice
  • NF-kappa B / genetics
  • NF-kappa B / immunology
  • NF-kappa B / metabolism
  • Peptides / pharmacology*
  • Protein Binding / drug effects
  • Protein Binding / genetics
  • Protein Binding / immunology
  • Protein Structure, Secondary / genetics
  • Protein Structure, Tertiary / genetics
  • Sequestosome-1 Protein
  • p38 Mitogen-Activated Protein Kinases / immunology
  • p38 Mitogen-Activated Protein Kinases / metabolism


  • Adaptor Proteins, Signal Transducing
  • CCAAT-Enhancer-Binding Proteins
  • Heat-Shock Proteins
  • Immunologic Factors
  • NF-kappa B
  • Peptides
  • SQSTM1 protein, human
  • Sequestosome-1 Protein
  • Sqstm1 protein, mouse
  • p38 Mitogen-Activated Protein Kinases