In this study we have generated a EYFP targeted to the mitochondrial intermembrane space (MIMS-EYFP) to determine for the first time the pH within this compartment. The fragment encoding HAI-tagged EYFP was fused with the C-terminus of glycerol-phosphate dehydrogenase, an integral protein of the inner mitochondrial membrane. Human ECV304 cells transiently transfected with MIMS-EYFP showed the typical mitochondrial network, co-localized with MitoTracker Red. Following the calibration procedure, an estimation of the pH value in the intermembrane space was obtained. This value (6.88 ± 0.09) was significantly lower than that determined in the cytosol after transfection with a cytosolic EYFP (7.59 ± 0.01). Further, the pH of the mitochondrial matrix, determined with a EYFP targeted to this subcompartment, was 0.9 pH units higher than that in the intermembrane space. In conclusion, MIMS-EYFP represents a novel powerful tool to monitor pH changes in the mitochondrial intermembrane space of live cells.

pH difference across the outer mitochondrial membrane measured with a green fluorescent protein mutant

PORCELLI, ANNA MARIA;GHELLI, ANNA MARIA;ZANNA, CLAUDIA;RUGOLO, MICHELA
2005

Abstract

In this study we have generated a EYFP targeted to the mitochondrial intermembrane space (MIMS-EYFP) to determine for the first time the pH within this compartment. The fragment encoding HAI-tagged EYFP was fused with the C-terminus of glycerol-phosphate dehydrogenase, an integral protein of the inner mitochondrial membrane. Human ECV304 cells transiently transfected with MIMS-EYFP showed the typical mitochondrial network, co-localized with MitoTracker Red. Following the calibration procedure, an estimation of the pH value in the intermembrane space was obtained. This value (6.88 ± 0.09) was significantly lower than that determined in the cytosol after transfection with a cytosolic EYFP (7.59 ± 0.01). Further, the pH of the mitochondrial matrix, determined with a EYFP targeted to this subcompartment, was 0.9 pH units higher than that in the intermembrane space. In conclusion, MIMS-EYFP represents a novel powerful tool to monitor pH changes in the mitochondrial intermembrane space of live cells.
A. M.PORCELLI; A. GHELLI; C. ZANNA; P. PINTON; R. RIZZUTO; M.RUGOLO
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/2389
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