Direct binding of the ligand PSG17 to CD9 requires a CD9 site essential for sperm-egg fusion.

@article{Ellerman2003DirectBO,
  title={Direct binding of the ligand PSG17 to CD9 requires a CD9 site essential for sperm-egg fusion.},
  author={Diego A. Ellerman and Cam T. Ha and Paul Primakoff and Diana Gold Myles and Gabriela S. Dveksler},
  journal={Molecular biology of the cell},
  year={2003},
  volume={14 12},
  pages={
          5098-103
        }
}
The function currently attributed to tetraspanins is to organize molecular complexes in the plasma membrane by using multiple cis-interactions. Additionally, the tetraspanin CD9 may be a receptor that binds the soluble ligand PSG17, a member of the immunoglobulin superfamily (IgSF)/CEA subfamily. However, previous data are also consistent with the PSG17 receptor being a CD9 cis-associated protein. In the current study, CD9 extracellular loop (EC2) specifically bound to PSG17-coated beads… CONTINUE READING