Interaction of S-SCAM with Neural Plakophilin-RelatedArmadillo-Repeat Protein/δ-Catenin ☆

Abstract Synaptic scaffolding molecule (S-SCAM) is a multiple PDZ domain-containing protein, which interacts with neuroligin, a cell adhesion molecule, and the NMDA receptor. In this study, we searched for S-SCAM-interacting proteins and obtained a neuralplakophilin-related armadillo -repeat protein (NPRAP)/δ-catenin. NPRAP/δ-catenin bound to the last PDZ domain of S-SCAM via its carboxyl-terminus in three different cell-free assay systems, was coimmunoprecipitated with S-SCAM from rat crude synaptosomes, and was localized at the excitatory synapses in rat hippocampal neurons. NPRAP/δ-catenin may be implicated in the molecular organization of synaptic junctions through the interaction with S-SCAM.