[HTML][HTML] Presence of immunoreactive α3 subunit isoform of Na, K-ATPase in mitochondria of kidney
CS Chang, RG Kirk, P Lee - Kidney international, 1998 - Elsevier
CS Chang, RG Kirk, P Lee
Kidney international, 1998•ElsevierBackground Sodium-potassium-adenosinetriphosphatase (Na, K-ATPase) is the primary
membrane enzyme responsible for the reabsorption of sodium ions in the kidney. It is known
that in the nephron the major subunit isoforms of Na, K-ATPase are α1 and β1. Previous
reports on the presence of α2 and α3 isoforms in the kidney were mixed and controversial.
Methods Techniques of ultrathin cryosectioning and immunoelectron microscopy were used
to study the distribution of α subunit isoforms (α1, α2, α3) and β subunit (β1 isoform) of Na, K …
membrane enzyme responsible for the reabsorption of sodium ions in the kidney. It is known
that in the nephron the major subunit isoforms of Na, K-ATPase are α1 and β1. Previous
reports on the presence of α2 and α3 isoforms in the kidney were mixed and controversial.
Methods Techniques of ultrathin cryosectioning and immunoelectron microscopy were used
to study the distribution of α subunit isoforms (α1, α2, α3) and β subunit (β1 isoform) of Na, K …
Background
Sodium-potassium-adenosinetriphosphatase (Na,K-ATPase) is the primary membrane enzyme responsible for the reabsorption of sodium ions in the kidney. It is known that in the nephron the major subunit isoforms of Na,K-ATPase are α1 and β1. Previous reports on the presence of α2 and α3 isoforms in the kidney were mixed and controversial.
Methods
Techniques of ultrathin cryosectioning and immunoelectron microscopy were used to study the distribution of α subunit isoforms (α1, α2, α3) and β subunit (β1 isoform) of Na,K-ATPase in renal tubular cells. Western blot analysis was used to show the presence of the α3 isoform in the extract of kidney mitochondria.
Results
We were able to confirm the previous finding that the α1 isoform and the β1 isoform were the preponderant isoforms of the α and β subunits of Na,K-ATPase in the basolateral membrane. In addition, we unexpectedly found the presence of the α3 isoform in the mitochondria of rat renal tubular cells. The α2 and α3 isoforms were not observed in either the apical or basolateral membrane.
Conclusions
Both immunoelectron microscopy and Western blot analysis of the rat kidney mitochondria confirm the presence of the α3 isoform of Na,K-ATPase in the rat kidney mitochondria. The function of this enzyme in the mitochondria is not clear at this time.
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