A functional AMPA receptor-calcium channel complex in the postsynaptic membrane

Ca²⁺ channels play critical roles in the regulation of synaptic activity. In contrast to the well established function of voltage-activated Ca²⁺ channels in the presynaptic membrane for neurotransmitter release, some studies are just beginning to elucidate the functions of the Ca²⁺ channels in the postsynaptic membrane. In this study, we demonstrated the functional association of α-amino-3-hydroxy-5-methyl-4- isoxazolepropionate (AMPA) receptors with the neuronal Ca²⁺ channels. A series of biochemical studies showed the specific association of Ca _v2.1 (α_1A-class) and Ca_v2.2 (α_1B-class) with AMPA receptors in the postsynaptic membrane. Our electrophysiological and Ca²⁺ imaging analyses of recombinant Ca_v2.1 and AMPA receptors also showed functional coupling of the two channels. Considering the critical roles of postsynaptic intracellular concentration of Ca²⁺ ([Ca²⁺]_i) increase and AMPA receptor trafficking for long-term potentiation (LTP) and long-term depression (LTD), the functional association of Ca²⁺ channels with the AMPA receptors may provide new insights into the mechanism of synaptic plasticity.