Synaptic targeting of the postsynaptic density protein PSD-95 mediated by lipid and protein motifs.
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.
Craven
S E
SE
Department of Physiology and Program in Neuroscience, University of California, San Francisco 94143-0444, USA.
El-Husseini
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AE
Bredt
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DS
D000818:Animals; D002478:Cells, Cultured; D003001:Cloning, Molecular; D000076122:Disks Large Homolog 4 Protein; D005455:Fluorescent Antibody Technique; D049452:Green Fluorescent Proteins; D051528:Guanylate Kinases; D006624:Hippocampus / Q000166:cytology / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins; D050356:Lipid Metabolism; D008055:Lipids / Q000502:physiology*; D008164:Luminescent Proteins / Q000235:genetics; D008565:Membrane Proteins; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D019308:Palmitic Acid / Q000378:metabolism; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013569:Synapses / Q000378:metabolism / Q000502:physiology*; D014162:Transfection; D025521:Tumor Suppressor Proteins
D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008055:Lipids; D008164:Luminescent Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; D025521:Tumor Suppressor Proteins; C033652:postsynaptic density proteins; D049452:Green Fluorescent Proteins; D019308:Palmitic Acid; C496468:DLG2 protein, human; D051528:Guanylate Kinases