Specific recognition of linear ubiquitin chains by the Npl4 zinc finger (NZF) domain of the HOIL-1L subunit of the linear ubiquitin chain assembly complex

Proc Natl Acad Sci U S A. 2011 Dec 20;108(51):20520-5. doi: 10.1073/pnas.1109088108. Epub 2011 Dec 2.

Abstract

The linear ubiquitin chain assembly complex (LUBAC) is a key nuclear factor-κB (NF-κB) pathway component that produces linear polyubiquitin chains. The HOIL-1L subunit of LUBAC has been shown to bind linear chains; however, detailed structural and functional analyses on the binding between LUBAC and linear chains have not been performed. In this study, we found that the Npl4 zinc finger (NZF) domain of HOIL-1L specifically binds linear polyubiquitin chains and determined the crystal structure of the HOIL-1L NZF domain in complex with linear diubiquitin at 1.7-Å resolution. The HOIL-1L NZF domain consists of a zinc-coordinating "NZF core" region and an additional α-helical "NZF tail" region. The HOIL-1L NZF core binds both the canonical Ile44-centered hydrophobic surface on the distal ubiquitin and a Phe4-centered hydrophobic patch on the proximal ubiquitin, representing a mechanism for the specific recognition of linear chains. The NZF tail binds the proximal ubiquitin to enhance the binding affinity. These recognition mechanisms were supported by the accompanying in vitro and in vivo structure-based mutagenesis experiments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Carrier Proteins / chemistry*
  • Crystallography, X-Ray / methods
  • Humans
  • Mice
  • Molecular Conformation
  • Molecular Sequence Data
  • NF-kappa B / metabolism
  • Nuclear Proteins / chemistry*
  • Protein Conformation
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid
  • Surface Plasmon Resonance / methods
  • Transcription Factors
  • Ubiquitin-Protein Ligases / chemistry*

Substances

  • Carrier Proteins
  • HOIL-1L protein, mouse
  • NF-kappa B
  • NPLOC4 protein, human
  • Npl4 protein, mouse
  • Nuclear Proteins
  • Transcription Factors
  • RBCK1 protein, human
  • Ubiquitin-Protein Ligases

Associated data

  • PDB/3B08
  • PDB/3B0A