ABSTRACT Chemical synapse assembly is an essential process underlying the development and plasticity of neural circuits. Synaptogenesis involves a complex sequence of coordinated events requiring many components in presynaptic and postsynaptic cells. Because these specialized junctions are organized and modified locally in response to a range of developmental or external stimuli, synapse formation is highly regulated. Decades of research have identified many relevant signaling pathways and factors that control the stages of synapse development in a range of systems. In this search, invertebrate models such as the neuromuscular junctions (NMJs) of Drosophila and C. elegans have offered sophisticated tools for identifying and dissecting mechanisms underlying the assembly and maturation of the sites of neurotransmitter release. This proposal aims to leverage unpublished discoveries suggesting that the Transforming Acidic Coiled-Coil (TACC) family serves to control synaptic protein synthesis via interactions with eIF-4E and other factors. Preliminary findings suggest that Drosophila dTACC occupies postsynaptic location that forms in response to active zone assembly and serves to regulate synapse development. We find that dTACC physically interacts with factors associated with translation including eIF-4E and CPEB/Orb2, and dTACC appears necessary and sufficient to control the protein level of the postsynaptic kinase dPak that regulates assembly of glutamate receptor clusters. This fabric of data leads us to a working model where (1) postsynaptic dTACC acts to inhibit the translation of dPak, and possibly other factors, thus controlling the extent and/or timing of synapse maturation. Moreover, we postulate that (2) dTACC activity is controlled by upstream trans-synaptic signaling events that coordinate NMJ development. Our goals are to test these two central ideas in order to open a robust new line of inquiry into mechanisms of postsynaptic translational regulation in this powerful model synapse. While our working model draws upon classic work on the eIF-4E-Binding Protein Maskin/TACC3 during early development, the TACC protein family has yet to be appreciated in this capacity at the neuronal synapse, thus presenting an exciting opportunity to identify a new mechanism for this conserved family of proteins that may be relevant in other nervous systems.