title: Electron tomographic structure and protein composition of isolated rat cerebellar, hippocampal and cortical postsynaptic densities.
abstract: Electron tomography and immunogold labeling were used to analyze similarities and differences in the morphology and protein composition of postsynaptic densities (PSDs) isolated from adult rat cerebella, hippocampi, and cortices. There were similarities in physical dimensions and gross morphology between cortical, hippocampal and most cerebellar PSDs, although the morphology among cerebellar PSDs could be categorized into three distinct groups. The majority of cerebellar PSDs were composed of dense regions of protein, similar to cortical and hippocampal PSDs, while others were either composed of granular or lattice-like protein regions. Significant differences were found in protein composition and organization across PSDs from the different brain regions. The signaling protein, βCaMKII, was found to be a major component of each PSD type and was more abundant than αCaMKII in both hippocampal and cerebellar PSDs. The scaffold molecule PSD-95, a major component of cortical PSDs, was found absent in a fraction of cerebellar PSDs and when present was clustered in its distribution. In contrast, immunogold labeling for the proteasome was significantly more abundant in cerebellar and hippocampal PSDs than cortical PSDs. Together, these results indicate that PSDs exhibit remarkable diversity in their composition and morphology, presumably as a reflection of the unique functional demands placed on different synapses.
authors.affiliation: The Department of Neurobiology and Anatomy, University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, United States; Graduate School of Biomedical Science, University of Texas Health Science Center at Houston, Houston, TX 77030, United States. Electronic address: Madeline.M.Burgoyne@uth.tmc.edu.
authors.forename: M M
authors.initials: MM
authors.lastname: Farley
authors.affiliation: The Department of Neurobiology and Anatomy, University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, United States. Electronic address: mswulius@caltech.edu.
authors.forename: M T
authors.initials: MT
authors.lastname: Swulius
authors.affiliation: The Department of Neurobiology and Anatomy, University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, United States. Electronic address: M.N.Waxham@uth.tmc.edu.
authors.forename: M N
authors.initials: MN
authors.lastname: Waxham
mesh_terms: D000818:Animals; D015153:Blotting, Western; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism; D002531:Cerebellum / Q000378:metabolism / Q000648:ultrastructure*; D002540:Cerebral Cortex / Q000378:metabolism / Q000648:ultrastructure*; D055032:Electron Microscope Tomography; D004591:Electrophoresis, Polyacrylamide Gel; D006624:Hippocampus / Q000378:metabolism / Q000648:ultrastructure*; D007150:Immunohistochemistry; D008297:Male; D057907:Post-Synaptic Density / Q000378:metabolism / Q000648:ultrastructure*; D017207:Rats, Sprague-Dawley
chemical_list: D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2
keywords: electron cryotomography; electron tomography; immunogold labeling; postsynaptic density; receptors; scaffold proteins