A Study of the Spatial Protein Organization of the Postsynaptic Density Isolated from Porcine Cerebral Cortex and Cerebellum

Abstract

Postsynaptic density (PSD) is a protein supramolecule lying underneath the postsynaptic membrane of excitatory synapses and has been implicated to play important roles in synaptic structure and function in mammalian central nervous system. Here, PSDs were isolated from two distinct regions of porcine brain, cerebral cortex and cerebellum. SDS-PAGE and Western blotting analyses indicated that cerebral and cerebellar PSDs consisted of a similar set of proteins with noticeable differences in the abundance of various proteins between these samples. Subsequently, protein localization in these PSDs was analyzed by using the Nano-Depth-Tagging method. This method involved the use of three synthetic reagents, as agarose beads whose surface was covalently linked with a fluorescent, photoactivable, and cleavable chemical crosslinker by spacers of varied lengths. After its application was verified by using a synthetic complex consisting of four layers of different proteins, the Nano-Depth-Tagging method was used here to yield information concerning the depth distribution of various proteins in the PSD. The results indicated that in both cerebral and cerebellar PSDs, glutamate receptors, actin, and actin binding proteins resided in the peripheral regions within ϳ10 nm deep from the surface and that scaffold proteins, tubulin subunits, microtubule-binding proteins, and membrane cytoskeleton proteins found in mammalian erythrocytes resided in the interiors deeper than 10 nm from the surface in the PSD. Finally, by using the immunoabsorption method, binding partner proteins of two proteins residing in the interiors, PSD-95 and ␣-tubulin, and those of two proteins residing in the peripheral regions, elongation factor-1␣ and calcium, calmodulin-dependent protein kinase II ␣ subunit, of cerebral and cerebellar PSDs were identified. Overall, the results indicate a striking similarity in protein organization between the PSDs isolated from porcine cerebral cortex and cerebellum.

Actinin-4 Governs Dendritic Spine Dynamics and Promotes Their Remodeling by Metabotropic Glutamate Receptors

“…Mass spectrometry studies indicate that actinins are components of the postsynaptic density (PSD) (56,57), underscoring their presence at postsynaptic sites. Consistent with biochemical findings, Actn2, for which ultrastructural information is available, has been shown to localize in apposition to the PSD and the spine apparatus within dendritic spines (58).…”

Dendritic spine alterations in schizophrenia

“…As a result, MAP2 is an important regulator of dendritic development and plasticity [26–31]. As a core constituent of the post-synaptic density in spines [32], MAP2 also binds filamentous actin [33]. Because dendritic spine plasticity depends on actin and microtubule dynamics, it is thus not surprising that spine plasticity is also effected by MAP2 [34–38].…”

Cerebellar Fastigial Nucleus Electrical Stimulation Alleviates Depressive-Like Behaviors in Post-Stroke Depression Rat Model and Potential Mechanisms

“…Moreover, anti-depressant therapy with citalopram reversed both the antineurogenic and the behavioral impacts of persistent stress following brain ischemia [8]. Recently, it was reported that the cerebellum may exhibit a role in psychiatric illness, behavior and cognition [9, 10]. Cerebellum dysfunction might be involved in pathogenesis of PSD, based on the correlation between the cerebellum and the affective disorder, similarity in pathology between PSD and neuropsychiatric diseases (particularly for depression), and the clinical trial indicating that cerebella substantially relives symptom of PSD upon activation [10].…”

“…Recently, it was reported that the cerebellum may exhibit a role in psychiatric illness, behavior and cognition [9, 10]. Cerebellum dysfunction might be involved in pathogenesis of PSD, based on the correlation between the cerebellum and the affective disorder, similarity in pathology between PSD and neuropsychiatric diseases (particularly for depression), and the clinical trial indicating that cerebella substantially relives symptom of PSD upon activation [10]. But there is little evidence that investigates the putative cerebellar effect in PSD [11].…”