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postsynaptic density
An electron-dense (by electron microscopy) thickening of the postsynaptic membrane. It is a protein-rich organelle specialized for signal transduction.
Size: 30-40 nm thick & a few hundred nm wide
Components:
1) glutamate receptors
a) NMDA receptors
b) AMPA receptors
c) metabotropic glutamate receptors (group 1)
-> linked to phospholipase C
2) adhesion receptors
a) ephA receptor
b) ephB receptor
3) scaffold proteins
a) homer
b) Shank
c) GKAP (disks large associated protein 1)
d) scaffold-associated protein-90 (SAP-90, PSD-95)
e) Rack-1 protein
f) Pick-1 protein
g) glutamate receptor-interacting protein-1
h) scaffold-associated protein-102
i) post synaptic density-93
j) scaffold-associated protein-97
Associated proteins:
1) SPAR
2) drebrin-1
mRNA translation occurs at post-synpatic densities & is tightly regulated by synaptic stimulation
Solubility: relatively insoluble in non-ionic detergents
Purification: differential centrifugation
General
organelle
Properties
CELL-REGION: dendritic spine
CELL: neuron
References
- Sheng M.
Molecular organization of the postsynaptic specialization.
Proc Natl Acad Sci U S A. 2001 Jun 19;98(13):7058-61. Review.
PMID: 11416187