Neurite fasciculation mediated by complexes of axonin-1 and Ng cell adhesion molecule.

Abstract

Neural cell adhesion molecules composed of immunoglobulin and fibronectin type III-like domains have been implicated in cell adhesion, neurite outgrowth, and fasciculation. Axonin-1 and Ng cell adhesion molecule (NgCAM), two molecules with predominantly axonal expression exhibit homophilic interactions across the extracellular space (axonin- 1/axonin-1 and NgCAM/NgCAM) and a heterophilic interaction (axonin-1-NgCAM) that occurs exclusively in the plane of the same membrane (cis-interaction). Using domain deletion mutants we localized the NgCAM homophilic binding in the Ig domains 1-4 whereas heterophilic binding to axonin-1 was localized in the Ig domains 2-4 and the third FnIII domain. The NgCAM-NgCAM interaction could be established simultaneously with the axonin-1-NgCAM interaction. In contrast, the axonin-1-NgCAM interaction excluded axonin-1/axonin-1 binding. These results and the examination of the coclustering of axonin-1 and NgCAM at cell contacts, suggest that intercellular contact is mediated by a symmetric axonin-12/NgCAM2 tetramer, in which homophilic NgCAM binding across the extracellular space occurs simultaneously with a cis-heterophilic interaction of axonin-1 and NgCAM. The enhanced neurite fasciculation after overexpression of NgCAM by adenoviral vectors indicates that NgCAM is the limiting component for the formation of the axonin-12/NgCAM2 complexes and, thus, neurite fasciculation in DRG neurons.

• Authors: S Kunz, M Spirig, C Ginsburg, A Buchstaller, P Berger, R Lanz, C Rader, L Vogt, B Kunz, P Sonderegger
• Journal: The Journal of cell biology (J Cell Biol) Vol. 143 Issue 6 Pg. 1673-90 (Dec 14 1998) ISSN: 0021-9525 [Print] United States
• PMID: 9852159 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Cell Adhesion Molecules, Neuron-Glia
• Cell Adhesion Molecules, Neuronal
• Cntn2 protein, mouse
• Contactin 2
• Recombinant Proteins

Topics

• Animals
• Animals, Newborn
• Binding Sites
• Cell Adhesion Molecules, Neuron-Glia (chemistry, genetics, physiology)
• Cell Adhesion Molecules, Neuronal (chemistry, genetics, physiology)
• Chickens
• Contactin 2
• Extracellular Space (physiology)
• Ganglia, Spinal (physiology)
• Mice
• Mice, Inbred ICR
• Models, Molecular
• Mutagenesis
• Neurites (physiology)
• Neurons (cytology, physiology)
• Organ Culture Techniques
• Point Mutation
• Polymerase Chain Reaction
• Protein Conformation
• Recombinant Proteins (chemistry, metabolism)
• Sequence Deletion
• Transfection