EMERGING ROLES OF DLG-LIKE PDZ PROTEINS IN THE ORGANIZATION OF THE NMDA-TYPE GLUTAMATERGIC SYNAPSE

A group of proteins found at cell+cell junctions have a common structu ral domain, called PDZ-a stretch of 80-90 amino acid residues initiall y identified in the three proteins PSD-95, Dig, and ZO-1. This domain is found in various proteins from bacteria to mammals and is involved in protein-protein interaction. Recently, many proteins containing thi s domain were identified in the nervous system hy molecular cloning an d shown to interact with other synaptic proteins, including various tr ansmitter receptors, ion channels, and signal transducers. These PDZ-c ontaining proteins are mostly located near the synaptic membrane and a re, therefore, speculated to transport associated proteins to the syna pse and/or anchor them at the synaptic sites, Alternatively, as a sing le molecule often contains multiple PDZ domains that can interact with each other, it may cluster all these synaptic molecules and facilitat e their signaling at synaptic sites, This review focuses on the best c haracterized PDZ-containing proteins that interact with N-methyl-D-asp artate (NMDA)type glutamate receptors and discusses their functions in synaptic organization.