Triple effect of mimetic peptides interfering with neural cell adhesion molecule homophilic cis interactions.
The neural cell adhesion molecule (NCAM) is pivotal in neural development, regeneration, and learning. Here we characterize two peptides, termed P1-B and P2, derived from the homophilic binding sites in the first two N-terminal immunoglobulin (Ig) modules of NCAM, with regard to their effects on neurite extension and adhesion. To evaluate how interference of these mimetic peptides with NCAM homophilic interactions in cis influences NCAM binding in trans, we employed a coculture system in which PC12-E2 cells were grown on monolayers of fibroblasts with or without NCAM expression and the rate of neurite outgrowth subsequently was analyzed. P2, but not P1-B, induced neurite outgrowth in the absence of NCAM binding in trans. When PC12-E2 cells were grown on monolayers of NCAM-expressing fibroblasts, the effect of both P1-B and P2 on neurite outgrowth was dependent on peptide concentrations. P1-B and P2 acted as conventional antagonists, agonists, and reverse agonists of NCAM at low, intermediate, and high peptide concentrations, respectively. The demonstrated in vitro triple pharmacological effect of mimetic peptides interfering with the NCAM homophilic cis binding will be valuable for the understanding of the actions of these mimetics in vivo.
Li
Shizhong
S
Protein Laboratory, Institute of Molecular Pathology, Panum Institute Bld. 6.2., University of Copenhagen, Blegdamsvej 3C, DK-2200, Copenhagen N, Denmark.
Kolkova
Kateryna
K
Rudenko
Olga
O
Soroka
Vladislav
V
Poulsen
Flemming M
FM
Bock
Elisabeth
E
Berezin
Vladimir
V
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001665:Binding Sites; D018920:Coculture Techniques; D005816:Genetic Complementation Test; D007739:L Cells; D051379:Mice; D008958:Models, Molecular; D018716:Molecular Mimicry; D016297:Mutagenesis, Site-Directed; D019006:Neural Cell Adhesion Molecules / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016501:Neurites / Q000378:metabolism / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D016716:PC12 Cells; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014162:Transfection
D019006:Neural Cell Adhesion Molecules; D010446:Peptide Fragments; D011994:Recombinant Proteins