Fig. 4.

Role of Cys1047 in the formation of an intermolecular disulfide bridge in the Ca²⁺ channel α₂δ-1 subunit. (A) Total cell lysates from HEK293 cells transiently transfected with plasmid cDNA encoding the full length α₂δ-1 or the α₂ peptide were incubated with (+) or without (−) 100 mM DTT as described in Section 2. The samples were analyzed by SDS-PAGE and visualized by western blotting using the anti-α₂δ-1 antibodies. Cells transfected with empty vector were used as the control (pIRES). (B) Cell lysates from HEK293 cells expressing different auxiliary subunits mutated in the extracellular loop of δ were analyzed by SDS-PAGE and western blotting under reducing (+) and non-reducing (−) conditions using the same anti-α₂δ-1 antibodies. (C) HEK293 cells were transiently transfected with plasmid cDNA coding the α₂δ-1 WT and the mutant proteins Cys1047Ser and C6 and analyzed by Western blot under reducing and non-reducing conditions.