Figure 1.

Illustration of the cardiac voltage gated L-type Ca_V1.2 channel complex. The channel consists of a pore-forming Ca_Vα_1C subunit and auxiliary subunits Ca_Vβ and Ca_Vα₂δ. The Ca_Vα_1c is composed of four homologous repeat domains (I-IV), each having six transmembrane spanning segments (S1–S6, shown in blue). S1–S4 comprise the voltage sensing domain (VSD) and S5–S6 form the pore domain (PD). Ca_Vβ subunits (depicted in purple) are composed of a SH3, HOOK, and GK domain. Interaction of Ca_Vβ with the Ca_Vα₁c occurs between the GK domain on Ca_Vβ subunits and the alpha interaction domain (AID) on the I-II linker (orange). Ca_Vα₂δ subunits are proposed to interact with the extracellular loops of domains I-III as highlighted by the red dashed lines [10,11,12,13].