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. 2020 Feb 11;21(4):e49113. doi: 10.15252/embr.201949113

Figure 1. Light‐activated proton pump mitochondria‐ON (mtON) is expressed in mitochondria.

Figure 1

  1. Schematic depicting the targeting strategy to localize mtON to the mitochondrial inner membrane (IM). The electron transport chain (ETC) complexes generate the endogenous mitochondrial PMF by proton pumping, represented by the + and − across the IM. Mitochondrial ATP synthase utilizes the PMF to convert ADP to ATP. The N‐terminal mitochondria‐target sequence from the IMMT1 protein shown in red; GFP shown in green. In response to light, mtON pumps protons from the mitochondrial matrix to the intermembrane space (IMS).
  2. Confocal images demonstrate overlap of GFP‐tagged mtON with MitoTracker™ Red CMXRos‐stained Caenorhabditis elegans hypodermal mitochondria. Scale bar 10 μm.
  3. Immunoblot comparing the cytosolic supernatant and the mitochondria‐enriched pellet of isolation fractions. GFP‐tagged mtON migrates at the predicted molecular weight of 82 kDa accounting for the mitochondria‐target sequence, the proton pump, and GFP. mtON is observed only in the mitochondrial fraction compared to marker proteins HSP60 (mitochondria) and actin (cytosol). All blots are from the same lanes on one membrane.