title: PSD-95 is required to sustain the molecular organization of the postsynaptic density.
abstract: PSD-95, a membrane-associated guanylate kinase, is the major scaffolding protein in the excitatory postsynaptic density (PSD) and a potent regulator of synaptic strength. Here we show that PSD-95 is in an extended configuration and positioned into regular arrays of vertical filaments that contact both glutamate receptors and orthogonal horizontal elements layered deep inside the PSD in rat hippocampal spine synapses. RNA interference knockdown of PSD-95 leads to loss of entire patches of PSD material, and electron microscopy tomography shows that the patchy loss correlates with loss of PSD-95-containing vertical filaments, horizontal elements associated with the vertical filaments, and putative AMPA receptor-type, but not NMDA receptor-type, structures. These observations show that the orthogonal molecular scaffold constructed from PSD-95-containing vertical filaments and their associated horizontal elements is essential for sustaining the three-dimensional molecular organization of the PSD. Our findings provide a structural basis for understanding the functional role of PSD-95 at the PSD.
authors.affiliation: Laboratories of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Chen
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Nelson
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.forename: Christine A
authors.initials: CA
authors.lastname: Winters
authors.forename: Rita
authors.initials: R
authors.lastname: Azzam
authors.forename: Alioscka A
authors.initials: AA
authors.lastname: Sousa
authors.forename: Richard D
authors.initials: RD
authors.lastname: Leapman
authors.forename: Harold
authors.initials: H
authors.lastname: Gainer
authors.forename: Morgan
authors.initials: M
authors.lastname: Sheng
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Reese
mesh_terms: D000818:Animals; D003599:Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D000076122:Disks Large Homolog 4 Protein; D004622:Embryo, Mammalian; D005260:Female; D049452:Green Fluorescent Proteins / Q000235:genetics; D006624:Hippocampus / Q000166:cytology; D007150:Immunohistochemistry / Q000379:methods; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D016086:Lentivirus / Q000502:physiology; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008954:Models, Biological; D009474:Neurons / Q000166:cytology*; D057907:Post-Synaptic Density / Q000378:metabolism* / Q000648:ultrastructure*; D034622:RNA Interference / Q000502:physiology; D051381:Rats; D018091:Receptors, AMPA / Q000378:metabolism / Q000648:ultrastructure; D013569:Synapses / Q000502:physiology / Q000648:ultrastructure; D014162:Transfection / Q000379:methods
chemical_list: D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D018091:Receptors, AMPA; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins