Polymorphic adhesion molecules neurexin and neuroligin (NL) mediate asymmetric trans-synaptic adhesion, which is crucial for synapse development and function. It is not known whether or how individual synapse function is controlled by the interactions between variants and isoforms of these molecules with differing ectodomain regions. At a physiological concentration of Ca(2+), the ectodomain complex of neurexin-1 beta isoform (Nrx1beta) and NL1 spontaneously assembled into crystals of a lateral sheet-like superstructure topologically compatible with transcellular adhesion. Correlative light-electron microscopy confirmed extracellular sheet formation at the junctions between Nrx1beta- and NL1-expressing non-neuronal cells, mimicking the close, parallel synaptic membrane apposition. The same NL1-expressing cells, however, did not form this higher-order architecture with cells expressing the much longer neurexin-1 +/- isoform, suggesting a functional discrimination mechanism between synaptic contacts made by different isoforms of neurexin variants.
Representative scheme of Neuroligin structure and an image from PDBsum server
Databases
PDB-Sum
3VKF Previously Class, Architecture, Topology and Homologous superfamily - PDB-Sum server
FSSP
3VKFFold classification based on Structure-Structure alignment of Proteins - FSSP server
