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Expression, regulation and function of Na,K-ATPase in the lens.
Prog Retin Eye Res. 2004 Nov; 23(6):593-615.PR

Abstract

Na,K-ATPase is responsible for maintaining the correct concentrations of sodium and potassium in lens cells. Na,K-ATPase activity is different in the two cell types that make up the lens, epithelial cells and fibers; specific activity in the epithelium is higher than in fibers. In some parts of the fiber mass Na,K-ATPase activity is barely detectable. There is a large body of evidence that suggests Na,K-ATPase-mediated ion transport by the epithelium contributes significantly to the regulation of ionic composition in the entire lens. In some species different Na,K-ATPase isoforms are present in epithelium and fibers but in general, fibers and epithelium express a similar amount of Na,K-ATPase protein. Turnover of Na,K-ATPase by protein synthesis may contribute to preservation of high Na,K-ATPase activity in the epithelium. In ageing lens fibers, oxidation, and glycation may decrease Na,K-ATPase activity. Na,K-ATPase activity in lens fibers and epithelium also may be subject to regulation as the result of protein tyrosine phosphorylation. Moreover, activation of G protein-coupled receptors by agonists such as endothelin-1 elicits changes of Na,K-ATPase activity. The asymmetrical distribution of Na,K-ATPase activity in the epithelium and fibers may contribute to ionic currents that flow in and around the lens. Studies on human cataract and experimental cataract in animals reveal changes of Na,K-ATPase activity but no clear pattern is evident. However, there is a convincing link between abnormal elevation of lens sodium and the opacification of the lens cortex that occurs in age-related human cataract.

Authors+Show Affiliations

Department of Ophthalmology and Visual Sciences, School of Medicine, Louisville, Kentucky, USA. delamere@louisville.eduNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.
Review

Language

eng

PubMed ID

15388076

Citation

Delamere, Nicholas A., and Shigeo Tamiya. "Expression, Regulation and Function of Na,K-ATPase in the Lens." Progress in Retinal and Eye Research, vol. 23, no. 6, 2004, pp. 593-615.
Delamere NA, Tamiya S. Expression, regulation and function of Na,K-ATPase in the lens. Prog Retin Eye Res. 2004;23(6):593-615.
Delamere, N. A., & Tamiya, S. (2004). Expression, regulation and function of Na,K-ATPase in the lens. Progress in Retinal and Eye Research, 23(6), 593-615.
Delamere NA, Tamiya S. Expression, Regulation and Function of Na,K-ATPase in the Lens. Prog Retin Eye Res. 2004;23(6):593-615. PubMed PMID: 15388076.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Expression, regulation and function of Na,K-ATPase in the lens. AU - Delamere,Nicholas A, AU - Tamiya,Shigeo, PY - 2004/9/25/pubmed PY - 2005/1/7/medline PY - 2004/9/25/entrez SP - 593 EP - 615 JF - Progress in retinal and eye research JO - Prog Retin Eye Res VL - 23 IS - 6 N2 - Na,K-ATPase is responsible for maintaining the correct concentrations of sodium and potassium in lens cells. Na,K-ATPase activity is different in the two cell types that make up the lens, epithelial cells and fibers; specific activity in the epithelium is higher than in fibers. In some parts of the fiber mass Na,K-ATPase activity is barely detectable. There is a large body of evidence that suggests Na,K-ATPase-mediated ion transport by the epithelium contributes significantly to the regulation of ionic composition in the entire lens. In some species different Na,K-ATPase isoforms are present in epithelium and fibers but in general, fibers and epithelium express a similar amount of Na,K-ATPase protein. Turnover of Na,K-ATPase by protein synthesis may contribute to preservation of high Na,K-ATPase activity in the epithelium. In ageing lens fibers, oxidation, and glycation may decrease Na,K-ATPase activity. Na,K-ATPase activity in lens fibers and epithelium also may be subject to regulation as the result of protein tyrosine phosphorylation. Moreover, activation of G protein-coupled receptors by agonists such as endothelin-1 elicits changes of Na,K-ATPase activity. The asymmetrical distribution of Na,K-ATPase activity in the epithelium and fibers may contribute to ionic currents that flow in and around the lens. Studies on human cataract and experimental cataract in animals reveal changes of Na,K-ATPase activity but no clear pattern is evident. However, there is a convincing link between abnormal elevation of lens sodium and the opacification of the lens cortex that occurs in age-related human cataract. SN - 1350-9462 UR - https://www.unboundmedicine.com/medline/citation/15388076/Expression_regulation_and_function_of_NaK_ATPase_in_the_lens_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1350-9462(04)00054-0 DB - PRIME DP - Unbound Medicine ER -