Acute inactivation of PSD-95 destabilizes AMPA receptors at hippocampal synapses.
Postsynatptic density protein (PSD-95) is a 95 kDa scaffolding protein that assembles signaling complexes at synapses. Over-expression of PSD-95 in primary hippocampal neurons selectively increases synaptic localization of AMPA receptors; however, mice lacking PSD-95 display grossly normal glutamatergic transmission in hippocampus. To further study the scaffolding role of PSD-95 at excitatory synapses, we generated a recombinant PSD-95-4c containing a tetracysteine motif, which specifically binds a fluorescein derivative and allows for acute and permanent inactivation of PSD-95. Interestingly, acute inactivation of PSD-95 in rat hippocampal cultures rapidly reduced surface AMPA receptor immunostaining, but did not affected NMDA or transferrin receptor localization. Acute photoinactivation of PSD-95 in dissociated neurons causes ∼80% decrease in GluR2 surface staining observed by live-cell microscopy within 15 minutes of PSD-95-4c ablation. These results confirm that PSD-95 stabilizes AMPA receptors at postsynaptic sites and provides insight into the dynamic interplay between PSD-95 and AMPA receptors in live neurons.
Department of Anatomy & Neurobiology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico. Guillermo.yudowski@upr.edu
Guillermo A
GA
Yudowski
Olav
O
Olsen
Hillel
H
Adesnik
Kurt W
KW
Marek
David S
DS
Bredt
D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D000076122:Disks Large Homolog 4 Protein; D006624:Hippocampus / Q000166:cytology* / Q000378:metabolism / Q000528:radiation effects; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D051665:Kv1.4 Potassium Channel / Q000378:metabolism; D008027:Light; D008565:Membrane Proteins / Q000378:metabolism*; D057054:Molecular Imaging; D009474:Neurons / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects; D055550:Protein Stability / Q000528:radiation effects; D021381:Protein Transport / Q000528:radiation effects; D017966:Pyramidal Cells / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects; D051381:Rats; D018091:Receptors, AMPA / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism* / Q000528:radiation effects
D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D051665:Kv1.4 Potassium Channel; D008565:Membrane Proteins; D018091:Receptors, AMPA; C104722:glutamate receptor ionotropic, AMPA 2