title: PSD-95 promotes the stabilization of young synaptic contacts.
abstract: Maintaining a population of stable synaptic connections is probably of critical importance for the preservation of memories and functional circuitry, but the molecular dynamics that underlie synapse stabilization is poorly understood. Here, we use simultaneous time-lapse imaging of post synaptic density-95 (PSD-95) and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) to investigate the dynamics of protein composition at axodendritic (AD) contacts. Our data reveal that this composition is highly dynamic, with both proteins moving into and out of the same synapse independently, so that synapses cycle rapidly between states in which they are enriched for none, one or both proteins. We assessed how PSD-95 and CaMKII interact at stable and transient AD sites and found that both phospho-CaMKII and PSD-95 are present more often at stable than labile contacts. Finally, we found that synaptic contacts are more stable in older neurons, and this process can be mimicked in younger neurons by overexpression of PSD-95. Taken together, these data show that synaptic protein composition is highly variable over a time-scale of hours, and that PSD-95 is probably a key synaptic protein that promotes synapse stability.
authors.affiliation: Department of Biology, Brandeis University, , Waltham, MA 02454, USA.
authors.forename: Christine E
authors.initials: CE
authors.lastname: Taft
authors.forename: Gina G
authors.initials: GG
authors.lastname: Turrigiano
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism*; D002478:Cells, Cultured; D000076122:Disks Large Homolog 4 Protein; D049452:Green Fluorescent Proteins / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008055:Lipids; D008565:Membrane Proteins / Q000378:metabolism*; D008568:Memory / Q000502:physiology*; D056004:Molecular Dynamics Simulation; D051381:Rats; D020318:Rats, Long-Evans; D013569:Synapses / Q000502:physiology*; D013997:Time Factors; D059008:Time-Lapse Imaging
chemical_list: D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008055:Lipids; C086724:Lipofectamine; D008565:Membrane Proteins; D049452:Green Fluorescent Proteins; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2
keywords: CaMKII; GluA2; PSD-95; synapse stabilization, live imaging