The Postsynaptic Density: There Is More than Meets the Eye.
The postsynaptic density (PSD), apparent in electron micrographs as a dense lamina just beneath the postsynaptic membrane, includes a deeper layer, the "pallium", containing a scaffold of Shank and Homer proteins. Though poorly defined in traditionally prepared thin-section electron micrographs, the pallium becomes denser and more conspicuous during intense synaptic activity, due to the reversible addition of CaMKII and other proteins. In this Perspective article, we review the significance of CaMKII-mediated recruitment of proteins to the pallium with respect to both the trafficking of receptors and the remodeling of spine shape that follow synaptic stimulation. We suggest that the level and duration of CaMKII translocation and activation in the pallium will shape activity-induced changes in the spine.
Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH) Bethesda, MD, USA.
Ayse
A
Dosemeci
Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill Chapel Hill, NC, USA.
Richard J
RJ
Weinberg
Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH) Bethesda, MD, USA.
Thomas S
TS
Reese
Electron Microscopy Facility, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH) Bethesda, MD, USA.
Jung-Hwa
JH
Tao-Cheng
CaMKII; EM; Homer; PSD; Shank; electron microscopy; pallium; postsynaptic density