AMPA receptor synaptic targeting regulated by stargazin interactions with the Golgi-resident PDZ protein nPIST.
Regulation of AMPA receptors (AMPARs) at synapses plays a critical role in alterations of synaptic strength in the brain. Stargazin, an AMPAR-interacting protein, is critical for clustering and regulation of synaptic AMPARs. Stargazin interacts with AMPARs via its extracellular domain and with PDZ [postsynaptic density-95 (PSD-95)/Discs large (Dlg)/zona occludens-1 (ZO-1)] proteins via its C-terminal PDZ-binding motif, and these interactions are necessary for stargazin and AMPAR synaptic targeting. By studying the expression of stargazin mutant constructs in cultured hippocampal neurons, we identified a novel domain corresponding to residues 243-283 within the cytoplasmic C terminus of stargazin that is also required for stargazin and AMPAR synaptic clustering. To identify proteins that interact with this stargazin synaptic clustering domain, we performed a yeast two-hybrid assay and found that this stargazin domain binds to nPIST (neuronal isoform of protein-interacting specifically with TC10), a Golgi-enriched protein implicated in trafficking of transmembrane proteins. Using in situ hybridization, immunohistochemistry, coimmunoprecipitation studies, and biochemical fractionation, we found that stargazin and nPIST colocalize and interact in the brain. Finally, by studying AMPAR clustering in transfected hippocampal neurons, we found that overexpression of nPIST enhances AMPAR synaptic clustering, whereas transfection of a dominant-negative nPIST construct attenuates AMPAR synaptic clustering. These studies identify a novel stargazin domain necessary for synaptic clustering of AMPARs and suggest that nPIST and stargazin interactions play a critical role in AMPAR trafficking to the synapse.
Davee Department of Neurology and Clinical Neurosciences, Northwestern University Medical School, Chicago, Illinois 60611-3008, USA.
Adolfo E
AE
Cuadra
Sheng-Han
SH
Kuo
Yoshimi
Y
Kawasaki
David S
DS
Bredt
Dane M
DM
Chetkovich
D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D019556:COS Cells; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D002522:Chlorocebus aethiops; D000076122:Disks Large Homolog 4 Protein; D006056:Golgi Apparatus / Q000378:metabolism*; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D017403:In Situ Hybridization; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D051381:Rats; D018091:Receptors, AMPA / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism*; D020741:rho GTP-Binding Proteins / Q000378:metabolism*
C491911:Cacng2 protein, rat; D015220:Calcium Channels; D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D018091:Receptors, AMPA; C033652:postsynaptic density proteins; C503262:Rhoq protein, rat; D020741:rho GTP-Binding Proteins