Defining the binding interface of Amyloid Precursor Protein (APP) and Contactin3 (CNTN3) by site-directed mutagenesis

PLoS One. 2019 Jul 18;14(7):e0219384. doi: 10.1371/journal.pone.0219384. eCollection 2019.


The Amyloid Precursor Protein (APP) and Contactin (CNTN) families of cell-surface proteins have been intensively studied in the context of neural development and neuropsychiatric diseases. Earlier studies demonstrated both genetic and biochemical interactions between the extracellular domains of APP and CNTN3, but their precise binding interfaces were not defined. In the present study, we have used binding assays between APP-alkaline phosphatase (AP) fusion proteins and CNTN-Fc fusion proteins, together with alanine substitution mutagenesis, to show that: (i) the second Fibronectin domain (Fn(2)) in CNTN3 mediates APP binding; (ii) the copper binding domain (CuBD) in APP mediates CNTN3 binding; and (iii) the most important amino acids for APP-CNTN3 binding reside on one face of CNTN3-Fn(2) and on one face of APP-CuBD. These experiments define the regions of direct contact that mediate the binding interaction between APP and CNTN3.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acids / metabolism
  • Amyloid beta-Protein Precursor / chemistry
  • Amyloid beta-Protein Precursor / metabolism*
  • Animals
  • Contactins / chemistry*
  • Contactins / metabolism*
  • HEK293 Cells
  • Humans
  • Mice
  • Models, Molecular
  • Mutagenesis, Site-Directed*
  • Protein Binding


  • Amino Acids
  • Amyloid beta-Protein Precursor
  • Cntn3 protein, mouse
  • Contactins