Solution structures of the adhesion molecule DdCAD-1 reveal new insights into Ca(2+)-dependent cell-cell adhesion
Lin, Z., Sriskanthadevan, S., Huang, H.B., Siu, C.H., Yang, D.W.(2006) Nat Struct Mol Biol 13: 1016-1022
- PubMed: 17057715
- DOI: https://doi.org/10.1038/nsmb1162
- Primary Citation of Related Structures:
1YHP, 2B1O - PubMed Abstract:
DdCAD-1 is a novel Ca(2+)-dependent cell adhesion molecule that lacks a hydrophobic signal peptide and a transmembrane domain. DdCAD-1 is expressed by the social amoeba Dictyostelium discoideum at the onset of development. It is synthesized as a soluble protein and then transported to the plasma membrane by contractile vacuoles. Here we describe the novel features of the solution structures of Ca(2+)-free and Ca(2+)-bound monomeric DdCAD-1. DdCAD-1 contains two beta-sandwich domains, belonging to the betagamma-crystallin and immunoglobulin fold classes, respectively. Whereas the N-terminal domain has a major role in homophilic binding, the C-terminal domain tethers the protein to the cell membrane. From structural and mutational analyses, we propose a model for the Ca(2+)-bound DdCAD-1 dimer as a basis for understanding DdCAD-1-mediated cell-cell adhesion at the molecular level. Our results provide new insights into Ca(2+)-dependent mechanisms for cell-cell adhesion.
Organizational Affiliation:
Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543.