NBD-independent nucleotide activation. Representative examples of the effect of 1 mM MgATP on Kir6.2-G334D/SUR-KAKA channels (A) or Kir6.2-G334DΔC channels (B). Patch excision and the start of the perfusion with nucleotide-free solution are indicated by the arrows and MgATP application by the bars. The dotted line indicates the zero current level.