Neuronal calcium channel α₁ subunit interacts with AMPA receptor, increasing its cell surface localisation

Voltage-activated Ca²⁺ channels (Ca_v) play critical roles in excitable cells including neurons. Unlike the well-defined roles of Ca_v2 for pre-synaptic neurotransmission, the post-synaptic function of Ca_v2 is unclear. Based on our previous study demonstrating the postsynaptic association of the Ca_v2 with the AMPA receptor (AMPA-R), in this study we sought to further analyse the Ca_v2-AMPA-R association. We used a step-by-step dissociation of partially purified native Ca_v2-AMPA-R complexes and co-immunoprecipitation of the Ca_v2-AMPA-R complexes expressed in HEK293T cells to demonstrate that the main subunit of Ca_v, α₁, formed a complex with the AMPA-R without the auxiliary subunits β, α₂δ, γ_2/3. The α₁ subunit increased the cell-surface localisation of the AMPA-R, which could be a post-synaptic function of the Ca_v2.