Distribution of lens sodium-potassium-adenosine triphosphatase

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Purpose. The specific activity of sodium-potassium-adenosine triphosphatase (Na-K-ATPase) in lens fiber cells is lower than the specific activity in lens epithelium. To test whether there is a reduction in the expression of Na-K-ATPase molecules in lens fibers, a Western blot technique was used. Methods. Membrane material was isolated from different regions of the rabbit lens. Na-K-ATPase (adenosine triphosphate hydrolysis) activity was measured in each membrane sample and Western blots were performed using an antibody to rabbit kidney Na-K-ATPase. Results. By immunoblotting, Na-K- ATPase polypeptide was detected in all lens cells. In contrast, adenosine triphosphate hydrolysis by the Na-K-ATPase (Na-K-ATPase activity) was not detectable or was detectable only at very low levels in fiber membranes from the lens nucleus and in cortex. Conclusion. These findings suggest that plasma membrane adenosine triphosphatase enzyme responsible for sodium- potassium transport is expressed in newly formed lens fibers and the transport molecules are retained as the fibers age and are compressed toward the center of the lens. However, with fiber aging there is a loss of functional ability of the Na-K-ATPase to hydrolyze adenosine triphosphate.

Original languageEnglish (US)
Pages (from-to)2159-2163
Number of pages5
JournalInvestigative Ophthalmology and Visual Science
Volume34
Issue number7
StatePublished - 1993
Externally publishedYes

Fingerprint

Sodium-Potassium-Exchanging ATPase
Lenses
Adenosine Triphosphate
Membranes
Hydrolysis
Western Blotting
Rabbits
sodium-translocating ATPase
Immunoblotting
Adenosine Triphosphatases
Potassium
Epithelium
Sodium
Cell Membrane
Kidney
Peptides
Antibodies
Enzymes

Keywords

  • Ca-ATPase
  • immunoblot
  • lens
  • Na-K-ATPase
  • rabbit

ASJC Scopus subject areas

  • Ophthalmology

Cite this

Distribution of lens sodium-potassium-adenosine triphosphatase. / Delamere, Nicholas A; Dean, W. L.

In: Investigative Ophthalmology and Visual Science, Vol. 34, No. 7, 1993, p. 2159-2163.

Research output: Contribution to journalArticle

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AU - Dean, W. L.

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N2 - Purpose. The specific activity of sodium-potassium-adenosine triphosphatase (Na-K-ATPase) in lens fiber cells is lower than the specific activity in lens epithelium. To test whether there is a reduction in the expression of Na-K-ATPase molecules in lens fibers, a Western blot technique was used. Methods. Membrane material was isolated from different regions of the rabbit lens. Na-K-ATPase (adenosine triphosphate hydrolysis) activity was measured in each membrane sample and Western blots were performed using an antibody to rabbit kidney Na-K-ATPase. Results. By immunoblotting, Na-K- ATPase polypeptide was detected in all lens cells. In contrast, adenosine triphosphate hydrolysis by the Na-K-ATPase (Na-K-ATPase activity) was not detectable or was detectable only at very low levels in fiber membranes from the lens nucleus and in cortex. Conclusion. These findings suggest that plasma membrane adenosine triphosphatase enzyme responsible for sodium- potassium transport is expressed in newly formed lens fibers and the transport molecules are retained as the fibers age and are compressed toward the center of the lens. However, with fiber aging there is a loss of functional ability of the Na-K-ATPase to hydrolyze adenosine triphosphate.

AB - Purpose. The specific activity of sodium-potassium-adenosine triphosphatase (Na-K-ATPase) in lens fiber cells is lower than the specific activity in lens epithelium. To test whether there is a reduction in the expression of Na-K-ATPase molecules in lens fibers, a Western blot technique was used. Methods. Membrane material was isolated from different regions of the rabbit lens. Na-K-ATPase (adenosine triphosphate hydrolysis) activity was measured in each membrane sample and Western blots were performed using an antibody to rabbit kidney Na-K-ATPase. Results. By immunoblotting, Na-K- ATPase polypeptide was detected in all lens cells. In contrast, adenosine triphosphate hydrolysis by the Na-K-ATPase (Na-K-ATPase activity) was not detectable or was detectable only at very low levels in fiber membranes from the lens nucleus and in cortex. Conclusion. These findings suggest that plasma membrane adenosine triphosphatase enzyme responsible for sodium- potassium transport is expressed in newly formed lens fibers and the transport molecules are retained as the fibers age and are compressed toward the center of the lens. However, with fiber aging there is a loss of functional ability of the Na-K-ATPase to hydrolyze adenosine triphosphate.

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