, 2009). Here, our data reveal that CNIH-2/-3 selectively bind to GluA1 in hippocampal neurons, allowing GluA1A2 receptors to reach the surface, and suggest that CNIH-2/-3 interaction with non-GluA1 subunits is prevented by γ-8. Removal of CNIH-2/-3 also speeds up the deactivation kinetics of surface AMPARs, an effect attributable to the loss of GluA1A2 receptors, which deactivate more slowly than GluA2A3 receptors. Thus, our data point to a model in which the trafficking and gating of individual AMPARs are determined by the interplay of AMPAR subunits,
cornichons, and TARPs. Cnih2fl/fl and Cnih3fl/fl mice were generated by standard procedures Selleckchem PCI-32765 ( Figure S1 available online). GSK1120212 mouse Cnih2fl/fl and Cnih3fl/fl mice were first bred as homozygotes, and then Cnih2fl/fl mice were bred with Cnih3fl/fl mice and NEX-CRE mice. Importantly, homozygous Cnih2fl/fl and Cnih3fl/fl were indistinguishable from wild-type mice. In addition, the NEX-CRE Cnih2fl/fl (NexCnih2−/−) mice, in which CNIH-2 is deleted from all forebrain pyramidal neurons, appeared grossly normal, and breeding was Mendelian. We used three strategies to study the effects of deleting CNIH-2. Using Cnih2fl/fl mice, we (1) injected AAV-CRE-GFP into the hippocampus of postnatal day 0–2 (P0–P2) mouse pups and then made acute slices 3 weeks later; (2) made
hippocampal slice cultures at P6–P9, biolistically transfected neurons with CRE-GFP at 4 days in vitro (DIV), and recorded 2–3 weeks
later (see Experimental Procedures for details); and (3) crossed Cnih2fl/fl mice with because the NEX-CRE mouse line. In the first two sets of experiments, simultaneous recordings of AMPAR- and NMDAR-evoked excitatory postsynaptic currents (AMPAR- and NMDAR-eEPSCs, respectively) were made from a green-infected/-transfected CA1 pyramidal neuron expressing CRE and a neighboring control nongreen pyramidal neuron during stimulation of excitatory axons in stratum radiatum. This approach permitted a pairwise, internally controlled comparison of the consequence of our genetic manipulation. In the third approach using acute slices prepared from NexCnih2−/− mice, the ratio of the AMPAR- and NMDAR-eEPSCs was calculated and compared to wild-type neurons. CNIH-2 deletion in single neurons by P0–P2 injection (red circles) and in slice culture (black circles) caused a 54% reduction in AMPAR-eEPSCs (Figure 1A), but no change in NMDAR-eEPSCs (Figure 1B). Because there was no significant difference between the results from acute and cultured slices, the data were combined. CNIH-2 deletion also caused a speeding in the decay of AMPAR-EPSCs in acute slices. This included eEPSCs (Figure 1C) and miniature EPSCs (mEPSCs) (Figure 1E). Furthermore, mEPSC amplitude was reduced (Figure 1D), consistent with a reduction in AMPAR number at individual synapses.