Secreted form of amyloid β/A4 protein precursor (APP) binds to two distinct APP binding sites on rat B103 neuron-like cells through two different domains, but only one site is involved in neuritotropic activity

H. Ninomiya, J. M. Roch, Lee-Way Jin, T. Saitoh

Research output: Contribution to journalArticle

52 Scopus citations

Abstract

Recent studies have identified the Alzheimer's disease amyloid β/A4 protein precursor (APP) as atrophic and/or tropic protein on several types of cells, including fibroblasts, primary culture neurons, PC12 cells, and B103 neuron-like cells. Many trophic proteins bind heparin, and it is believed that the heparin-binding domain is crucial for the trophic activity of these proteins. APP also binds heparin. The current studies were undertaken to examine the hypothesis that the neuritotropic activity of APP requires heparin binding. It was found that APP produced in E. coli bound B103 cells through detergent-extractable molecules. Approximately 50% of the binding sites were heparinase-sensitive, and heparin and heparan sulfate competed for APP binding to these sites. The heparinase-insensitive sites were recognized by a stretch of 17 amino acids of APP (residues 319-335) that contains the neuritotropic activity of APP. A mutant APP with a deletion at this site was capable of binding to the heparinase-sensitive sites, although this molecule was not neuritotropic to B103 neuron-like cells. Therefore, the neuritotropic site and the heparin-binding site are distinct in APP, and the neuritotropic effect of APP is produced through its binding to detergent-extractable and heparinase-insensitive sites.

Original languageEnglish (US)
Pages (from-to)495-500
Number of pages6
JournalJournal of Neurochemistry
Volume63
Issue number2
StatePublished - Aug 1994

Keywords

  • Alzheimer's disease
  • Amyloid
  • Amyloid β/A4 protein precursor
  • Heparin
  • Neuritotropic activity

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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