latrunculin-a and echistatin

At synapses, cell adhesion molecules (CAMs) provide the molecular framework for coordinating signaling events across the synaptic cleft. Among synaptic CAMs, the integrins, receptors for extracellular matrix proteins and counterreceptors on adjacent cells, are implicated in synapse maturation and plasticity and memory formation. However, little is known about the molecular mechanisms of integrin action at central synapses. Here, we report that postsynaptic beta3 integrins control synaptic strength by regulating AMPA receptors (AMPARs) in a subunit-specific manner. Pharmacological perturbation targeting beta3 integrins promotes endocytosis of GluR2-containing AMPARs via Rap1 signaling, and expression of beta3 integrins produces robust changes in the abundance and composition of synaptic AMPARs without affecting dendritic spine structure. Importantly, homeostatic synaptic scaling induced by activity deprivation elevates surface expression of beta3 integrins, and in turn, beta3 integrins are required for synaptic scaling. Our findings demonstrate a key role for integrins in the feedback regulation of excitatory synaptic strength.

Topics: Animals; Bridged Bicyclo Compounds, Heterocyclic; Chelating Agents; Egtazic Acid; Endocytosis; Excitatory Amino Acids; Excitatory Postsynaptic Potentials; Gene Expression Regulation; Hippocampus; In Vitro Techniques; Integrin beta3; Intercellular Signaling Peptides and Proteins; Mice; Mice, Knockout; Neural Inhibition; Neurons; Patch-Clamp Techniques; Peptides; Platelet Aggregation Inhibitors; Presynaptic Terminals; rap1 GTP-Binding Proteins; Rats; Receptors, AMPA; Synapses; Thiazolidines; Time Factors; Transfection