The dynamics of SAP90/PSD-95 recruitment to new synaptic junctions

Mol Cell Neurosci. 2001 Aug;18(2):149-67. doi: 10.1006/mcne.2001.1012.


SAP90/PSD-95 is thought to be a central organizer of the glutamatergic synapse postsynaptic reception apparatus. To assess its potential role during glutamatergic synapse formation, we used GFP-tagged SAP90/PSD-95, time lapse confocal microscopy, and cultured hippocampal neurons to determine its dynamic recruitment into new synaptic junctions. We report that new SAP90/PSD-95 clusters first appeared at new axodendritic contact sites within 20-60 min of contact establishment. SAP90/PSD-95 clustering was rapid, with kinetics that fit a single exponential with a mean time constant of approximately 23 min. Most new SAP90/PSD-95 clusters were found juxtaposed to functional presynaptic boutons as determined by labeling with FM 4-64. No evidence was found for the existence of discrete transport particles similar to those previously reported to mediate presynaptic active zone cytoskeleton assembly. Instead, we found that SAP90/PSD-95 is recruited to nascent synapses from a diffuse dendritic cytoplasmic pool. Our findings show that SAP90/PSD-95 is recruited to nascent synaptic junctions early during the assembly process and indicate that its assimilation is fundamentally different from that of presynaptic active zone components.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Animals, Newborn
  • Cell Communication / physiology*
  • Cell Differentiation / physiology*
  • Cytosol / metabolism
  • Cytosol / ultrastructure
  • Dendrites / metabolism
  • Dendrites / ultrastructure
  • Glutamic Acid / metabolism
  • Green Fluorescent Proteins
  • Hippocampus / cytology
  • Hippocampus / growth & development*
  • Hippocampus / metabolism
  • Immunohistochemistry
  • Indicators and Reagents / pharmacokinetics
  • Intracellular Membranes / metabolism
  • Intracellular Membranes / ultrastructure
  • Kinetics
  • Luminescent Proteins / pharmacokinetics
  • Microscopy, Confocal
  • Nerve Tissue Proteins / metabolism*
  • Neurons / cytology
  • Neurons / metabolism*
  • Nonlinear Dynamics
  • Presynaptic Terminals / metabolism
  • Presynaptic Terminals / ultrastructure
  • Protein Transport / physiology*
  • Rats
  • Rats, Sprague-Dawley
  • SAP90-PSD95 Associated Proteins
  • Synapses / metabolism*
  • Synapses / ultrastructure
  • Time Factors
  • Transport Vesicles / metabolism
  • Transport Vesicles / ultrastructure


  • Indicators and Reagents
  • Luminescent Proteins
  • Nerve Tissue Proteins
  • SAP90-PSD95 Associated Proteins
  • Green Fluorescent Proteins
  • Glutamic Acid