Characterization of Cav1.4 Complexes (α11.4, β2, and α2δ4) in HEK293T Cells and in the Retina

摘要: In photoreceptor synaptic terminals, voltage-gated Cav1.4 channels mediate Ca(2+) signals required for transmission of visual stimuli. Like other high voltage-activated Cav channels, are composed a main pore-forming α1 subunit and auxiliary β α2δ subunits. Of the four distinct classes α2δ, β2 α2δ4 thought to co-assemble with subunits in photoreceptors. However, an understanding functional properties this combination is lacking. Here, we provide evidence that α1, β2, contribute channel complexes retina describe their electrophysiological recordings. addition, identified variant named here β2X13, which, along β2a, present terminals. were coimmunoprecipitated from lysates transfected HEK293 cells mouse found interact outer plexiform layer containing by proximity ligation assays. whole-cell patch clamp recordings HEK293T cells, (Cav1.4 + β2X13) exhibited weaker voltage-dependent activation than those α2δ1. Moreover, compared α2δ4) β2X13-containing greater inactivation. The latter effect was specific because it not seen Cav1.2 channels. Our results first detailed analysis form native indicate potential heterogeneity these conferred β2a β2X13 variants.