Opportunities to mine the neuronal synaptic proteome for molecules of relevance to the immune synapse. (A) Schematic diagram of the interaction between a T cell and a dendritic cell that is presenting an antigen. When T cells encounter antigen-presenting cells, sequential recruitment of adhesion molecules and cytoplasmic signaling molecules contribute to the local assembly of the immune synapse. The adaptor protein spinophilin bears PDZ and actin-binding domains that allow it to undergo relocalization, presumably to engage or convey important client proteins, in the formation of the immune synapse. (B) Relative mRNA expression levels of proteins containing PDZ domains (candidate scaffold/adaptor proteins) that are differentially distributed between lymphocytes and dendritic cells.