FIGURE 6.

Effects of organic cations on voltage-dependent movements of TMRM-labeled C260-TMRM, C380-TMRM, and C483-TMRM in the rOct1(10ΔC,G478C) mutant without and with modification of Cys-478 with MTSET⁺. rOct1(10ΔC,P260C,G478C), rOct1(10ΔC,F380C,G478C), and rOct1(10ΔC,F483C,G478C) were expressed in oocytes, and Cys-260, Cys-380, and Cys-483 were modified with TMRM. In part of the oocytes, additional modification of Cys-478 with MTSET⁺ was performed. The oocytes were superfused with Ori buffer (without organic cations) or Ori buffer containing 10 mm choline (choline⁺), 100 μm MPP⁺ (MPP⁺), or 100 μm TBuA⁺ (TBuA⁺). Measurements performed without organic cations are indicated by lines (for individual values see Fig. 5). Means ± S.E. of 4–6 oocytes from three different oocyte batches are indicated. The data show that the effects of organic cations were reduced and partially abolished by the G478C mutation and totally abolished after MTSET⁺ labeling of Cys-478.