AIDA-1 Moves out of the Postsynaptic Density Core under Excitatory Conditions

• Published in: PloS one 2015-09, Vol.10 (9), p.e0137216-e0137216
• Main Authors: Dosemeci, Ayse, Toy, Dana, Reese, Thomas S, Tao-Cheng, Jung-Hwa
• Format: Article
• Language: English
• Subjects: Amyloid beta-protein; Animals; Antibodies; Carrier Proteins - metabolism; Cells, Cultured; Density; Depolarization; Electron microscopy; Epitopes; Excitation; Genetic aspects; Hippocampus; Hippocampus - cytology; Immunoglobulins; Kinases; Laboratories; Localization; N-Methyl-D-aspartic acid; N-Methylaspartate - pharmacology; Neurobiology; Neurological disorders; Neurons; Neurons - cytology; Neurons - metabolism; Neurons - ultrastructure; Neurosciences; Physiological aspects; Post-Synaptic Density - drug effects; Post-Synaptic Density - metabolism; Post-Synaptic Density - ultrastructure; Postsynaptic density; Postsynaptic density proteins; Postsynaptic potentials; Potassium - pharmacology; Protein synthesis; Proteins; Proteomics; Rats, Sprague-Dawley; Rodents; Synaptic transmission; Translocation
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0137216

AIDA-1 is highly enriched in postsynaptic density (PSD) fractions and is considered a major component of the PSD complex. In the present study, immunogold electron microscopy was applied to determine localization as well as the activity-induced redistribution of AIDA-1 at the PSD using two antibodies that recognize two different epitopes. In cultured rat hippocampal neurons under basal conditions, immunogold label for AIDA-1 is mostly located within the dense core of the PSD, with a median distance of ~30 nm from the postsynaptic membrane. Under excitatory conditions, such as depolarization with high K+ (90 mM, 2 min) or application of NMDA (50 μM, 2 min), AIDA-1 label density at the PSD core is reduced to 40% of controls and the median distance of label from the postsynaptic membrane increases to ~55 nm. The effect of excitatory conditions on the postsynaptic distribution of AIDA-1 is reversed within 30 minutes after returning to control conditions. The reversible removal of AIDA-1 from the PSD core under excitatory conditions is similar to the redistribution of another abundant PSD protein, SynGAP. Both SynGAP-alpha1 and AIDA-1 are known to bind PSD-95. Activity-induced transient translocation of these abundant proteins from the PSD core could promote structural flexibility, vacate sites on PSD-95 for the insertion of other components and thus may create a window for synaptic modification.