Friday, March 30, 2007

Responding to Reduced CoA Levels

This from 'Metabolic Strategy Of Stressed Cell': at

"The scientists studied the response to decreased CoA in a mouse model by blocking CoA production with hopantenate (HoPan). HoPan is a chemical that interferes with pantothenate kinase (PanK), the enzyme that triggers the first step of CoA production. Following the shutdown of CoA production, the cells quickly recycled CoA from other jobs so it could concentrate all its efforts on a single task: extracting life-supporting energy from nutrients in the mitochondria. Mitochondria are the powerhouses of the cell, so-called because these bags of enzymes host a series of complex biochemical pathways that produce the energy-rich molecule ATPthe cell's "currency" with which it "buys" chemical reactions that consume energy.

"The cell's response to reduced CoA levels is like the driver of a car that is low on gas," said Charles Rock, Ph.D., a member of the St. Jude Infectious Diseases department and co-author of the paper. "The driver might try to save what little gas is left by turning off the air conditioner and driving slower," he said. "Likewise, by shutting down or limiting the other biochemical pathways that use CoA, the cell can concentrate it in the mitochondria where it's needed most."

"The metabolic changes we observed freed up the CoA to make ATP," said Suzanne Jackowski, Ph.D., a member of the St. Jude Infectious Diseases department and the paper's senior author. "Our study provides the first detailed look at how the cell shifts genetic gears to respond to a significant change in its ability to carry on its daily metabolic chores."

A cellular response that would be assumed to have resulted from genetic mistakes that make it through intricate DNA repair mechanisms and become fixed throughout a species as a result of enhanced fitness. We know the drill. An orderly, purposeful process also is consistent with intelligent design. So what standard dictates the choice of paradigms? Evidence that the above actually evolved from a system without a biochemical pathway brake? Or just knowing that it had to?



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