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Updated: May 18, 2026

Inner Mitochondrial Membrane Sensitivity to Na+ Reveals Partially Segmented Functional CoQ Pools
Published on: July 20, 2022
Restricted diffusion of OXPHOS complexes in dynamic mitochondria delays their exchange between cristae and engenders
Verena Wilkens1, Wladislaw Kohl, Karin Busch
1Department of Biology/Chemistry, Division of Mitochondrial Dynamics, University of Osnabrueck, 49069 Osnabrueck, Germany.
Abstract:
Mitochondria are involved in cellular energy supply, signaling and apoptosis. Their ability to fuse and divide provides functional and morphological flexibility and is a key feature in mitochondrial quality maintenance. To study the impact of mitochondrial fusion/fission on the reorganization of inner membrane proteins, oxidative phosphorylation (OXPHOS) complexes in mitochondria of different HeLa cells were tagged with fluorescent proteins (GFP and DsRed-HA), and cells were fused by polyethylene glycol treatment. Redistribution of the tagged OXPHOS complexes was then followed by means of immunoelectron microscopy, two color super-resolution fluorescence microscopy and single molecule tracking. In contrast to outer membrane and matrix proteins, which mix quickly and homogeneously upon mitochondrial fusion, the mixing of inner membrane proteins was decelerated. Our data suggest that the composition of cristae is preserved during fusion of mitochondria and that cristae with mixed OXPHOS complexes are only slowly and successively formed by restricted diffusion of inner membrane proteins into existing cristae. The resulting transitory mosaic composition of the inner mitochondrial membrane illuminates mitochondrial heterogeneity and potentially is linked to local differences in function and membrane potential.
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