Synaptic Targeting of the Postsynaptic Density Protein PSD-95 Mediated by Lipid and Protein Motifs

• Published in: Neuron (Cambridge, Mass.) Vol. 22; no. 3; pp. 497 - 509
• Main Authors: Craven, Sarah E, El-Husseini, Alaa E, Bredt, David S
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.03.1999
• Subjects: Animals; Cells, Cultured; Cloning, Molecular; Disks Large Homolog 4 Protein; Fluorescent Antibody Technique; Green Fluorescent Proteins; Guanylate Kinases; Hippocampus - cytology; Hippocampus - physiology; Intracellular Signaling Peptides and Proteins; Lipid Metabolism; Lipids - physiology; Luminescent Proteins - genetics; Membrane Proteins; Mutation; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; Nerve Tissue Proteins - physiology; Neuronal Plasticity - physiology; Neurons - metabolism; Neurons - physiology; Palmitic Acid - metabolism; Rats; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Synapses - metabolism; Synapses - physiology; Transfection; Tumor Suppressor Proteins
• ISSN: 0896-6273; 1097-4199
• DOI: 10.1016/S0896-6273(00)80705-9

During synaptic development, proteins aggregate at specialized pre- and postsynaptic structures. Mechanisms that mediate protein clustering at these sites remain unknown. To investigate this process, we analyzed synaptic targeting of a postsynaptic density protein, PSD-95, by expressing green fluorescent protein– (GFP-) tagged PSD-95 in cultured hippocampal neurons. We find that postsynaptic clustering relies on three elements of PSD-95: N-terminal palmitoylation, the first two PDZ domains, and a C-terminal targeting motif. In contrast, disruptions of PDZ3, SH3, or guanylate kinase (GK) domains do not affect synaptic targeting. Palmitoylation is sufficient to target the diffusely expressed SAP-97 to synapses, and palmitoylation cannot be replaced with alternative membrane association motifs, suggesting that a specialized synaptic lipid environment mediates postsynaptic clustering. The requirements for PDZ domains and a C-terminal domain of PSD-95 indicate that protein–protein interactions cooperate with lipid interactions in synaptic targeting.