postsynaptic density

Introduction

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:

• glutamate receptors
  • NMDA receptors
  • AMPA receptors
  • metabotropic glutamate receptors (group 1)
    • linked to phospholipase C
• adhesion receptors
  • ephA receptor
  • ephB receptor
• scaffold proteins
  • homer
  • Shank
  • GKAP (disks large associated protein 1)
  • scaffold-associated protein-90 (SAP-90, PSD-95)
  • Rack-1 protein
  • Pick-1 protein
  • glutamate receptor-interacting protein-1
  • scaffold-associated protein-102
  • post synaptic density-93
  • scaffold-associated protein-97

Associated proteins:

• SPAR
• 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

More general terms

• organelle