Neurons communicate with one another through specialized junctions called synapses that are so robust that they survive homogenization. Although several cell-surface receptor-ligand pairs have been proposed to participate in forming and maintaining synapses, one of the best families of candidates--the immunoglobulin-domain proteins--have only been found in invertebrates. Biederer et al. report that IGSF4 is a homophilic protein that can induce the formation of fully functional glutamatergic synapses when cotransfected into nonneural, vertebrate human embryonic kidney (HEK) cells along with glutamate receptors.
T. Biederer, Y. Sara, M. Mozhayeva, D. Atasoy, X. Liu, E. T. Kavalali, T. C. Südhof, SynCAM, a synaptic adhesion molecule that drives synapse assembly, Science 297, 1525-1531 (2002). [Abstract] [Full Text]