Continual remodeling of postsynaptic density and its regulation by synaptic activity


A postsynaptic density (PSD) protein, PSD-95, was tagged with green fluorescent protein (GFP-PSD-95) and expressed in cultured hippocampal neurons using recombinant adenoviruses. GFP-PSD-95 was selectively localized to excitatory postsynaptic sites. Time-lapse fluorescence imaging of hippocampal neurons revealed that >20% of GFP-PSD-95 clusters turned over within 24 hours. The appearance rate of clusters was higher than the disappearance rate, and this difference accounted for the gradual increase of the cluster density observed in culture. Dynamics of PSD-95 clusters were also inhibited by blockers of excitatory synaptic transmission. Continual PSD turnover and its regulation by synaptic activity may be important in activity-dependent remodeling of neuronal connections.

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Figure 1: Localization of GFP-PSD-95 to dendritic spines.
Figure 2: Localization of GFP-PSD-95 to excitatory postsynaptic sites.
Figure 3: Dynamic behavior of GFP-PSD-95 clusters.
Figure 4: Turnover of PSD-95 clusters in hippocampal pyramidal neurons on day 19 of culture.
Figure 5: Statistical analysis of PSD-95 turnover in hippocampal pyramidal neurons.
Figure 6: Increase of PSD-95 immunoreactive clusters in cultured hippocampal neurons.
Figure 7: Electrophysiological analysis of hippocampal pyramidal neurons in culture.
Figure 8: Turnover of PSD-95 clusters is regulated by synaptic activity.


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We thank Y. Kanegae and I. Saito for materials used in adenovirus construction. This work was supported by grants from the Agency of Industrial Science and Technology and Special Coordination Funds of the Science and Technology Agency of the Japanese Government.

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Correspondence to Shigeo Okabe.

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Okabe, S., Kim, H., Miwa, A. et al. Continual remodeling of postsynaptic density and its regulation by synaptic activity. Nat Neurosci 2, 804–811 (1999).

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