title: Organization of the core structure of the postsynaptic density.
abstract: Much is known about the composition and function of the postsynaptic density (PSD), but less is known about its molecular organization. We use EM tomography to delineate the organization of PSDs at glutamatergic synapses in rat hippocampal cultures. The core of the PSD is dominated by vertically oriented filaments, and ImmunoGold labeling shows that PSD-95 is a component of these filaments. Vertical filaments contact two types of transmembrane structures whose sizes and positions match those of glutamate receptors and intermesh with two types of horizontally oriented filaments lying 10-20 nm from the postsynaptic membrane. The longer horizontal filaments link adjacent NMDAR-type structures, whereas the smaller filaments link both NMDA- and AMPAR-type structures. The orthogonal, interlinked scaffold of filaments at the core of the PSD provides a structural basis for understanding dynamic aspects of postsynaptic function.
authors.affiliation: Laboratory of Neurobiology and Electron Microscopy Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Chen
authors.forename: Christine
authors.initials: C
authors.lastname: Winters
authors.forename: Rita
authors.initials: R
authors.lastname: Azzam
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.forename: James A
authors.initials: JA
authors.lastname: Galbraith
authors.forename: Richard D
authors.initials: RD
authors.lastname: Leapman
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Reese
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D000076122:Disks Large Homolog 4 Protein; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D008958:Models, Molecular; D051381:Rats; D017470:Receptors, Glutamate / Q000648:ultrastructure; D013569:Synapses / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D017470:Receptors, Glutamate