Crystal Structure of the V Domain of Human Nectin-like Molecule-1/Syncam3/Tsll1/Igsf4b, a Neural Tissue-specific Immunoglobulin-like Cell-Cell Adhesion Molecule
Dong, X., Xu, F., Gong, Y., Gao, J., Lin, P., Chen, T., Peng, Y., Qiang, B., Yuan, J., Peng, X., Rao, Z.(2006) J Biol Chem 281: 10610-10617
- PubMed: 16467305 
- DOI: https://doi.org/10.1074/jbc.M513459200
- Primary Citation of Related Structures:  
1Z9M - PubMed Abstract: 
Nectins are Ca(2+)-independent immunoglobulin (Ig) superfamily proteins that participate in the organization of epithelial and endothelial junctions. Nectins have three Ig-like domains in the extracellular region, and the first one is essential in cell-cell adhesion and plays a central role in the interaction with the envelope glycoprotein D of several viruses. Five Nectin-like molecules (Necl-1 through -5) with similar domain structures to those of Nectins have been identified. Necl-1 is specifically expressed in neural tissue, has Ca(2+)-independent homophilic and heterophilic cell-cell adhesion activity, and plays an important role in the formation of synapses, axon bundles, and myelinated axons. Here we report the first crystal structure of its N-terminal Ig-like V domain at 2.4 A, providing insight into trans-cellular recognition mediated by Necl-1. The protein crystallized as a dimer, and the dimeric form was confirmed by size-exclusion chromatography and chemical cross-linking experiments, indicating this V domain is sufficient for homophilic interaction. Mutagenesis work demonstrated that Phe(82) is a key residue for the adhesion activity of Necl-1. A model for homophilic adhesion of Necl-1 at synapses is proposed based on its structure and previous studies.
Organizational Affiliation: 
National Laboratory of Biomacromolecules, Institute of Biophysics (IBP), Chinese Academy of Sciences, Beijing 100101, China.