Fig. 5.

Targeting H⁺ sensors to RFP-tagged and GFP-tagged proteins. a Schematic of RNb fused to the pH sensor super-ecliptic pHluorin (RNb-SEpH) and bound to RFP. b Schematic of GNb-pHuji binding to RFP. c, d HeLa cells co-expressing RNb-SEpH and TOM20-mCh were imaged in modified HBS (MHBS) using epifluorescence microscopy and exposed to extracellular pH 6.5 (c) or pH 8 (d) in the presence of nigericin (10 μM). Scale bars 10 μm. e, f HeLa cells co-expressing GNb-pHuji and TOM20-GFP were exposed to extracellular pH 6.5 (e) or pH 8 (f) in the presence of nigericin. Scale bars 10 μm. g, h Timecourse from single cells of the fluorescence changes (F/F₀) of mitochondrially targeted RNb-SEpH or GNb-pHuji evoked by the indicated manipulations of extracellular pH. Results shown are representative of 3 independent experiments