Heterologous expression of α6α3β2β3-nAChR in human SH-EP1 cells. (A) α6/α3 chimera: Left, the chimera sequence with the ligand-binding N-terminal domain of the human α6, colored cyan, and C-terminal domain of the human α3, colored red. Right, the homology model of the α6/α3 chimera without the signal peptide with the colors matching the colors in the sequence. (B) A cartoon figure shows the process of the stably transfected α63β2β3 cell line. (C) A phase-contrast picture of SH-EP1-α6*-nAChR cells before patch-clamp recording. (D) A typical trace shows an ACh-induced inward whole-cell current in SH-EP1 cell transfected with this chimeric α6*-nAChR.