PDZ domains and the organization of supramolecular complexes

PDZ domains are modular protein interaction domains that bind in a sequence -specific fashion to short C-terminal peptides or internal peptides that fo ld in a beta -finger. The diversity of PDZ binding specificities can be exp lained by variable amino acids lining the peptide-binding groove of the PDZ domain. Abundantly represented in Caenorhabditis elegans, Drosophila melan ogaster, and mammalian genomes, PDZ domains are frequently found in multipl e copies or are associated with other protein-binding motifs in multidomain scaffold proteins. PDZ-containing proteins are typically involved in the a ssembly of supramolecular complexes that perform localized signaling functi ons at particular subcellular locations. Organization around a PDZ-based sc affold allows the stable localization of interacting proteins and enhances the rate and fidelity of signal transduction within the complex. Some PDZ-c ontaining proteins are more dynamically regulated in distribution and may a lso be involved in the trafficking of interacting proteins within the cell.