Question

) Inactivation provides a rapid means to change hormone concentrations.​

Answer 1

Answer:

Gene inactivation studies have shown that Na,K-ATPase is essential for life. Absence of expression of Na,K-ATPase α1 gene is developmentally lethal (229), even though the α1−/– embryos develop beyond the blastocyst stage (28). In contrast, α2−/– animals are born alive but die soon after birth, most probably as the result of respiratory trouble related to dysfunction of neuronal circuit involved in respiration control (222, 301), or of the diaphragmatic muscle. Heterozygous animal tissues for α1 or α2 genes inactivation display mostly cardiac phenotype, and support an important role of the α2 isoform in the intracellular homeostasis of calcium, particularly in heart, vascular smooth muscle, and glial tissues (129, 300, 361). Gene inactivation of the α3 and α4 isoforms has not been reported. Inactivation of the colonic H,K-ATPase affects mostly potassium homeostasis in the colon and kidney as discussed in the H,K-ATPases in Kidney section.

Only two human genetic diseases are known to be related to Na,K-ATPase gene. A familial form of hemiplegic migraine has been associated with mutations in the α2 gene (120) (OMIM ∑602481). These mutations appear to abolish or greatly reduce the function of the α2 isoform of Na,K-ATPase (86). Rapid-onset dystonia parkinsonism has been associated with inactivating mutation of the α3 gene (2) (OMIM ∑128235). In both cases, the mode of inheritance is dominant, suggesting that the disease is due to haploinsufficiency of the α2 and α3 isoform, respectively.