Effect of the pH
on the fluorescence intensities of ECFP or EYFP fused to the Kir2.1 channel. A. Images of HEK293T cell plasma membrane sheets expressing ECFP-Kir2.1 or Kir2.1-EYFP exposed to pHi 10.0 or 6.0. For clarity of presentation (but not during data analysis), the contrast of photos was increased by 20% with Photoshop CS3. B. Averaged effect of the pHi on the florescence intensities of ECFP-Kir2.1 or Kir2.1-EYFP in plasma sheets (C, n = 15). The fluorescence intensities were normalized to those obtained at pHi 10.0. *** indicates p < 0.005 compared to the pHi 10.0 value.