Biological complexity: mitochondria respond to oxygen lack (Introduction)

by David Turell , Thursday, November 07, 2019, 17:59 (1843 days ago) @ David Turell

Mitochondria switch metabolism of glycogen when oxygen is depleted:

https://phys.org/news/2019-11-oxygen-deficiency-rewires-mitochondria.html

"Mitochondria burn oxygen and provide energy for the body. Cells lacking oxygen or nutrients have to change their energy supply quickly in order to keep growing. Scientists from the Max Planck Institute for Biology of Ageing have now shown that mitochondria are reprogrammed under depleted oxygen and nutrients.

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"Cells adapt to oxygen deficiency by switching their energy supply to glycolysis, in which sugar is fermented without oxygen. This may be necessary in old age, for example, as the cells in the body are often less supplied with oxygen and nutrients. Also, cancer cells can face this problem, because some tumours have poor blood supply and thus little oxygen and nutrients reach the cells.

"'It has been known for some time that cells reduce the number of mitochondria when they lack oxygen and switch to glycolysis. We have now discovered that the remaining mitochondria are additionally reprogrammed to meet the new requirements," explains Max Planck Director Thomas Langer.

"This happens via a newly discovered signaling pathway in the cell: a protease in the membrane of mitochondria is activated during the conversion to glycolysis and then breaks down various proteins in the organelles. As a result, no new mitochondria can be formed and the remaining mitochondria change their metabolism. This process eventually stops on its own, as the protease begins to degrade itself at high activity. "This signaling pathway not only has a built-in timer, but also enables a very rapid response to oxygen deficiency," said Langer."

Comment: A highly designed protection system, as mitochondria are the energy engines for all cells which are in active production. Once cells were in active production, this mechanism had to have been there for protection from sudden unexpected oxygen loss. Requires the thinking a designing brain would have to recognize problems in advance of the design.