title: Zinc Stabilizes Shank3 at the Postsynaptic Density of Hippocampal Synapses.
abstract: Shank3 is a postsynaptic density (PSD) scaffold protein of the Shank family. Here we use pre-embedding immunogold electron microscopy to investigate factors influencing the distribution of Shank3 at the PSD. In dissociated rat hippocampal cultures under basal conditions, label for Shank3 was concentrated in a broad layer of the PSD, ~20-80 nm from the postsynaptic membrane. Upon depolarization with high K+ (90 mM, 2 min), or application of NMDA (50 μM, 2 min), both the labeling intensity at the PSD and the median distance of label from the postsynaptic membrane increased significantly, indicating that Shank3 molecules are preferentially recruited to the distal layer of the PSD. Incubation in medium supplemented with zinc (50 μM ZnCl2, 1 hr) also significantly increased labeling intensity for Shank3 at the PSD, but this addition of Shank3 was not preferential to the distal layer. When cells were incubated with zinc and then treated with NMDA, labeling intensity of Shank3 became higher than with either treatment alone and manifested a preference for the distal layer of the PSD. Without zinc supplementation, NMDA-induced accumulation of Shank3 at the PSD was transient, reversing within 30 min after return to control medium. However, when zinc was included in culture media throughout the experiment, the NMDA-induced accumulation of Shank3 was largely retained, including Shank3 molecules recruited to the distal layer of the PSD. These results demonstrate that activity induces accumulation of Shank3 at the PSD and that zinc stabilizes PSD-associated Shank3, possibly through strengthening of Shank-Shank association.
authors.affiliation: NINDS EM Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States of America.
authors.forename: Jung-Hwa
authors.initials: JH
authors.lastname: Tao-Cheng
authors.affiliation: Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States of America.
authors.forename: Dana
authors.initials: D
authors.lastname: Toy
authors.affiliation: Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States of America.
authors.forename: Christine A
authors.initials: CA
authors.lastname: Winters
authors.affiliation: Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States of America.
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Reese
authors.affiliation: Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States of America.
authors.forename: Ayse
authors.initials: A
authors.lastname: Dosemeci
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D002478:Cells, Cultured; D006624:Hippocampus / Q000378:metabolism; D008854:Microscopy, Electron / Q000379:methods; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D057907:Post-Synaptic Density / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D009419:Nerve Tissue Proteins; C120532:Shank3 protein, rat; D015032:Zinc