Biochemical controls: the kidney (Introduction)

by David Turell , Monday, April 25, 2022, 20:47 (526 days ago)

The kidney does manythings at once to produce proper urine:

https://medicalxpress.com/news/2022-04-key-urinary-kidney.html

"Proper function of the kidney is critical for concentrating urine, regulating blood pressure, and for the tight control of electrolyte levels in the blood. The kidney achieves these important functions through many microscopic functional units, called nephrons. These nephrons consist of different segments with distinct functions. How these segments form during development and how their function is maintained in the adult is only partially understood.

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"The distal nephron is particularly important for the ability of the kidney to concentrate urine, regulate blood pressure, and control calcium and magnesium blood levels. Parts of the distal nephron have specific salt transporters, which are the main targets of medicine's most effective diuretics, used in the treatment of hypertension and chronic kidney disease. Thus, understanding how their function is regulated has important implications for these common diseases.

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"Previously, Marneros showed in work published in Developmental Cell in 2020 that AP-2β is required for the formation of the segment of the distal nephron that is targeted by thiazide diuretics: the distal convoluted tubule. This prompted him to ask whether the closely related protein AP-2α also has a function in the kidney. His team found that while AP-2β function in the kidney is required for survival by regulating the development and function of distal convoluted tubules, AP-2α is important for the proper function of a different segment of the distal nephron, called the collecting duct, which is involved in the kidney's ability to concentrate urine. Notably, loss of even only half of AP-2β levels causes progressive kidney disease, whereas complete loss of AP-2α resulted in less severe kidney abnormalities.

"'These findings show that AP-2α and AP-2β are important regulators of distinct segments of the distal nephron. These new observations in genetic mouse models are important contributions to our understanding of how specific segments of the kidney are regulated on a molecular level," says Marneros."

Comment: As in all these situations, everything must work together from the start, or it won't work. That is irreducible complexity as must be fully designed from the start to work properly. Mutating it bit by bit is impossible. This intact functkon had to first appear in the Cambrian explosion.