Identification of a linear epitope in sortilin that partakes in pro-neurotrophin binding

J Biol Chem. 2010 Apr 16;285(16):12210-22. doi: 10.1074/jbc.M109.062364. Epub 2010 Feb 16.

Abstract

Sortilin acts as a cell surface receptor for pro-neurotrophins (pro-NT) that upon complex formation with the p75 neurotrophin receptor (p75(NTR)) is able to signal neuronal cell death. Here we screened a sortilin peptide library comprising 16-mer overlapping sequences for binding of the pro-domains of nerve growth factor and brain-derived neurotrophic factor. We find that a linear surface-exposed sequence, (163)RIFRSSDFAKNF(174), constitutes an important pro-NT binding epitope in sortilin. Systematic mutational analysis revealed residues Arg(163), Phe(165), Arg(166), and Phe(170) to be critical for the interaction. Expression of a sortilin mutant in which these four amino acids were substituted by alanines disrupted pro-NT binding without affecting receptor heterodimerization with p75(NTR) or binding of ligands that selectively engages the centrally located tunnel in the beta-propeller of sortilin. We furthermore demonstrate that a peptide comprising the ligand-binding epitope can prevent pro-NT-induced apoptosis in RN22 schwannoma cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Vesicular Transport / chemistry*
  • Adaptor Proteins, Vesicular Transport / genetics
  • Adaptor Proteins, Vesicular Transport / immunology
  • Adaptor Proteins, Vesicular Transport / metabolism*
  • Amino Acid Sequence
  • Amino Acid Substitution
  • Apoptosis
  • Base Sequence
  • Binding Sites / genetics
  • Cell Line
  • DNA Primers / genetics
  • Dimerization
  • Epitopes / chemistry
  • Epitopes / genetics
  • Epitopes / metabolism
  • Humans
  • In Vitro Techniques
  • Ligands
  • Models, Molecular
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Nerve Growth Factors / metabolism*
  • Nerve Tissue Proteins / chemistry
  • Nerve Tissue Proteins / metabolism
  • Protein Binding
  • Protein Precursors / metabolism
  • Receptors, Nerve Growth Factor / chemistry
  • Receptors, Nerve Growth Factor / metabolism
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / immunology
  • Recombinant Proteins / metabolism
  • Transfection

Substances

  • Adaptor Proteins, Vesicular Transport
  • DNA Primers
  • Epitopes
  • Ligands
  • NGFR protein, human
  • Nerve Growth Factors
  • Nerve Tissue Proteins
  • Protein Precursors
  • Receptors, Nerve Growth Factor
  • Recombinant Proteins
  • sortilin