Ayooshi Mitra, Amity University, Kolkata
Mitochondrial alternative oxidase (AOX) is an enzyme that forms an integral part of the electron transport chain (ETS) in mitochondria. This enzyme is present in the mitochondria of many invertebrates. The expression of AOX in human mitochondria is regarded as a potential therapeutic strategy, regardless of the reason for the occurrence of the enzyme in animal mitochondria. To date, quite some data is available due to heterologous AOX expression in animal cells, but there is no or very little data available on natively expressed AOX.
The research contributes significantly to the application of animals that express AOX natively. As a model for AOX activity analysis, the study considered the tardigrade, exemplaris. It was observed that in the presence of an AOX inhibitor, the tolerance of Hypsibius exemplaris to blockage of the mitochondrial respiratory chain (MRC) complexes was decreased. It was also noted that the inhibitor-sensitive respiration enabled tardigrade respiration under this blockage condition. In addition, although the detection of AOX at the protein level and the pronounced oxygraphic recording of its activity required the blockage of the MRC complex, the data obtained showed that AOX contributed to animal functioning. The researchers showed that AOX activity in tardigrades can be supervised by measuring the whole-body respiration of the intact specimen. In addition, the impact of MRC complex IV blockage on AOX expression and AOX inhibition in the absence of blockage on the functioning of animals could also be monitored.
Therefore, Hypsibius exemplaris is prospected to be a useful model organism for the study of the natively expressed mitochondrial alternative oxidase (AOX) enzyme as a whole-animal model. These analyses will help in estimating the impact of the AOX enzyme on animal behavior and the functioning of mitochondria under normal conditions as well as when subjected to external stress factors.
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Reference:
- Grobys D., Roszkowska M., Kaczmarek Ł., Jarmuszkiewicz W., Karachitos A., Kmita H. (2020). The Tardigrade Hypsibius Exemplaris as an Emerging Model to Study the Mitochondrial Alternative Oxidase at Animal Organismal Level. bioRxiv.https://www.biorxiv.org/content/10.1101/2020.12.09.417485v1.full
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