NCAM Mimetic Peptides: An Update

Abstract

The neural cell adhesion molecule (NCAM) is involved in multiple, relatively low affinity interactions with itself and with other cell surface receptors and growth factors. Its cytoplasmic domains do not posses any intrinsic enzymatic activity, which makes it difficult to develop reliable pharmacological tools interfering with NCAM functions. Recent progress in our understanding of the structural basis of NCAM-mediated cell adhesion and signaling has allowed a structure-based design of NCAM mimetic peptides. Using this approach, a number of peptides termed P2, P1-B, P-3-DE and P-3-G, whose sequences contain one or several NCAM homophilic binding sites involved in NCAM binding to itself, have been identified. By means of NMR titration analysis and molecular modeling, a number of peptides derived from NCAM and targeting NCAM heterophilic ligands, such as the fibroblast growth factor receptor and heparan sulfate proteoglycans, (HSPG) have been identified. The FGL, dekaCAM, FRM/EncaminA, BCL, EncaminC and EncaminE peptides, all target the FGF receptor, whereas the heparin-binding peptide HBP targets HSPG. Moreover, a number of NCAM-binding peptides have been identified employing screening of combinatorial peptide libraries. The C3 and NBP10 peptides target the first Ig module, whereas the ENFIN2 and ENFIN11 peptides target fibronectin type III (FN3) modules of NCAM. A number of NCAM mimetics can induce neurite outgrowth and exhibit neuroprotective and synaptic plasticity modulating properties in vitro and in vivo, making them attractive pharmacological tools suitable for drug development for the treatment of neurodegenerative disorders and impaired memory.