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

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.
Mesh Terms:
Adaptor Proteins, Vesicular Transport, Amino Acid Sequence, Amino Acid Substitution, Apoptosis, Base Sequence, Binding Sites, Cell Line, DNA Primers, Dimerization, Epitopes, Humans, In Vitro Techniques, Ligands, Models, Molecular, Molecular Sequence Data, Mutagenesis, Site-Directed, Nerve Growth Factors, Nerve Tissue Proteins, Protein Binding, Protein Precursors, Receptors, Nerve Growth Factor, Recombinant Proteins, Transfection
J. Biol. Chem.
Date: Apr. 16, 2010
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