Ca <sup>2+</sup> /calmodulin-kinase II enhances channel conductance of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate type glutamate receptors

DOI Web Site 被引用文献32件
  • Victor Derkach
    Vollum Institute, Oregon Health Sciences University, Portland, OR 97201
  • Andres Barria
    Vollum Institute, Oregon Health Sciences University, Portland, OR 97201
  • Thomas R. Soderling
    Vollum Institute, Oregon Health Sciences University, Portland, OR 97201

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<jats:p> The ability of central glutamatergic synapses to change their strength in response to the intensity of synaptic input, which occurs, for example, in long-term potentiation (LTP), is thought to provide a cellular basis for memory formation and learning. LTP in the CA1 field of the hippocampus requires activation of Ca <jats:sup>2+</jats:sup> /calmodulin-kinase II (CaM-KII), which phosphorylates Ser-831 in the GluR1 subunit of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate glutamate receptor (AMPA-R), and this activation/phosphorylation is thought to be a postsynaptic mechanism in LTP. In this study, we have identified a molecular mechanism by which CaM-KII potentiates AMPA-Rs. Coexpression in HEK-293 cells of activated CaM-KII with GluR1 did not affect the glutamate affinity of the receptor, the kinetics of desensitization and recovery, channel rectification, open probability, or gating. Single-channel recordings identified multiple conductance states for GluR1, and coexpression with CaM-KII or a mutation of Ser-831 to Asp increased the contribution of the higher conductance states. These results indicate that CaM-KII can mediate plasticity at glutamatergic synapses by increasing single-channel conductance of existing functional AMPA-Rs or by recruiting new high-conductance-state AMPA-Rs. </jats:p>

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