Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.17 (CaMKII)
 4,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Electron microscopy allows the analysis of synaptic ultrastructure and its modifications during learning or in pathological conditions. However, conventional electron microscopy uses aldehyde fixatives that alter the morphology of the synapse by changing osmolarity and collapsing its molecular components. We have used high-pressure freezing (HPF) to capture within a few milliseconds structural features without aldehyde fixative, and thus to provide a snapshot of living synapses. CA1 hippocampal area slices from P21 rats were frozen at -173 degrees C under high pressure to reduce crystal formation, and synapses on dendritic spines were analysed after cryosubstitution and embedding. Synaptic terminals were larger than after aldehyde fixation, and synaptic vesicles in these terminals were less densely packed. Small filaments linked the vesicles in subgroups. The postsynaptic densities (PSDs) exhibited filamentous projections extending into the spine cytoplasm. Tomographic analysis showed that these projections were connected with the spine cytoskeletal meshwork. Using immunocytochemistry, we found as expected GluR1 at the synaptic cleft and CaMKII in the PSD. Actin immunoreactivity (IR) labelled the cytoskeletal meshwork beneath the filamentous projections, but was very scarce within the PSD itself. ProSAP2/Shank3, cortactin and Ena/VASP-IRs were concentrated on the cytoplasmic face of the PSD, at the level of the PSD projections. Synaptic ultrastructure after HPF was different from that observed after aldehyde fixative. The boutons were larger, and filamentous components were preserved. Particularly, filamentous projections were observed linking the PSD to the actin cytoskeleton. Thus, synaptic ultrastructure can be analysed under more realistic conditions following HPF.
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PMID:Analysis of synaptic ultrastructure without fixative using high-pressure freezing and tomography. 1722 95

Although the expression of CaMKII and synaptic-associated proteins has been widely studied, the temporospatial distribution of CaMKII and NMDAR subunits in different hippocampal subregions during postnatal development still lacks detailed information. In this study, we used immunofluorescent staining to assess CaMKII and NR2B expressions and the relationship between them in CA1, CA3, and DG of rat hippocampus on postnatal (P) days: P0, P4, P7, P10, P14, P21, P28, and P56. The results showed that from P0 to P56, CaMKII expression increased gradually, while NR2B expression decreased gradually, and the time points of their expression peak differed in CA1, CA3, and DG during postnatal development. Although the expression of CaMKII was negatively correlated with NR2B in CA1 and DG, the coexpression of CaMKII with NR2B existed in CA1, CA3, and DG during postnatal development. Interestingly, after P21, CaMKII expression and the coexpression of CaMKII with NR2B became obvious in the Stratum lucidum of CA3. The specific temporospatial distribution pattern of CaMKII with NR2B might be related to the different physiological functions during postnatal development. Discovery of the alteration of the relationship between expression of CaMKII and NMDAR subunits may be helpful for understanding mechanisms and therapy of neurodegenerative diseases.
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PMID:Immunolocalization of CaMKII and NR2B in hippocampal subregions of rat during postnatal development. 2290 54