Defined tertiary structures allow proteins to bind to and communicate with other proteins. The PDZ domain, identified in several signaling proteins located at the plasma membrane, binds to a (T/S)XV motif found in the COOH-terminus of other proteins. Garner et al. review the role of the PDZ domain in protein complex assembly in pre- and postsynaptic membranes, and the formation of signaling "active zones."
Garner, C.C., Nash, J. and Huganir, R.L. (2000) PDZ domains in synapse assembly and signalling. Trends Cell Biol. 10: 274-280. [Online Journal]