Maturation of neural circuits demands the proper generation and elimination of synapses. -catenin (also known as NPRAP) has been implicated in the regulation of dendrite morphology, spine number and cognitive function. In neurons, delta-catenin is present in dendrites, and is enriched in the postsynaptic density as a component of the cadherin and catenin cell adhesion complex. Studies from our lab have shown the association of delta-catenin with the scaffolds, ABP, GRIP and PSD95, through a PDZ binding sequence, as well as the participation of delta-catenin in synaptic anchorage of GluR2-containing AMPA receptors. delta-catenin functions as a link between cadherins at adherens junctions and the PSD and its associated receptors through a direct interaction with synaptic scaffolding proteins via its PDZ ligand. In hippocampal neurons, exogenous expression of delta-catenin induces a dramatic change in the morphology of dendrites, including extensive production of actin-containing filopodia and lamellipodia-like structures. Association of delta-catenin with cortactin is required for these changes. Co-expression of GRIP/ABP or PSD95 inhibits the ability of delta-catenin to form filopodia- and lamellipodia-like structures suggesting that the scaffolds regulate the actin polymerization function of delta-catenin-cortactin. Interaction between delta-catenin and scaffolding proteins appears to be crucial for development of dendrites and spines in the central nervous system and maturation of neural circuits.