The function of the central nervous system depends on a large number of excitatory and inhibitory synapses. These axo-dendritic contact points are highly specialized for the fast transmission of information, a process that depends on a high concentration of neurotransmitter-gated ion channels in precise apposition to presynaptic nerve terminals releasing the appropriate neurotransmitter. During processes of synapse formation, submembraneous scaffolding proteins anchor and concentrate neurotransmitter receptors and associated factors at the postsynaptic side. The modulation of synaptic transmission, thought to underlay learning and memory processing, requires additional proteins specialized for i. ) signal transduction, ii. ) protein trafficking and iii. ) cytoskeletal rearrangements. Our main goals are to identify and characterize proteins at the postsynaptic compartment of synapses that contribute to synaptic formation and function.