scholarly journals Studies on lipids and the activity of Na,K-ATPase in lens fibre cells

1996 ◽  
Vol 314 (3) ◽  
pp. 961-967 ◽  
Author(s):  
William L. DEAN ◽  
Nicholas A. DELAMERE ◽  
Douglas BORCHMAN ◽  
Amy E. MOSELEY ◽  
Rajesh P. AHUJA
Keyword(s):  
Epithelial Cell ◽  
Cell Membrane ◽  
Atpase Activity ◽  
Lipid Composition ◽  
Cell Membranes ◽  
Lens Epithelium ◽  
Membrane Material ◽  
Fibre Cell ◽  
Lens Fibre ◽  
Lens Fibre Cell

Na,K-ATPase was studied in the two cell types that make up the lens of the eye. Membrane material was isolated from lens fibre cells, which make up the bulk of the lens cell mass, and also from lens epithelial cells, which are present only as a monolayer on the anterior lens surface. Judged by immunoblotting, greater amounts of Na,K-ATPase α1 and β1 polypeptides were found in fibre cell membrane material than in epithelial cell membrane material. However, the Na,K-ATPase activity in epithelial cell membrane material was 20 times that measured in fibre cell membrane material. In 86Rb uptake experiments with intact lenses, ouabain-inhibitable 86Rb uptake was observed for lens epithelium but not for lens fibres. These findings are consistent with a low Na,K-ATPase activity in lens fibre cells even though these cells express a considerable amount of Na,K-ATPase α1 and β1 polypeptides. The lipid composition of lens fibre cell membranes causes them to be more ordered than epithelial cell membranes; this was confirmed by measurements of the infrared CH2 symmetric stretching band frequency. Because lipid composition can influence Na,K-ATPase activity, experiments were conducted to determine whether the activity of Na,K-ATPase α1β1 is inhibited by lens fibre lipid. However, no significant difference in Na,K-ATPase activity was detected when Na,K-ATPase α1β1 was purified from rabbit kidney and then reconstituted with lipid that had been isolated from either lens epithelium or lens fibre cells. These studies indicate that lens fibre cells contain both Na,K-ATPase α1 and β1 polypeptides but have low Na,K-ATPase activity. However, the results do not support the notion that this is due to the lipid composition of lens fibre cell membranes.

Bfsp2 mutation found in mouse 129 strains causes the loss of CP49 and induces vimentin-dependent changes in the lens fibre cell cytoskeleton

2004 ◽  
Vol 78 (1) ◽  
pp. 109-123 ◽  
Author(s):  
Aileen Sandilands ◽  
Xin Wang ◽  
Aileen M Hutcheson ◽  
John James ◽  
Alan R Prescott ◽  
...  
Keyword(s):  
Fibre Cell ◽  
Cell Cytoskeleton ◽  
Lens Fibre ◽  
Lens Fibre Cell

Polypeptides of the lens fibre cell intracellular matrix

1980 ◽  
Vol 36 (4) ◽  
pp. 416-418 ◽  
Author(s):  
M. Katar ◽  
W. -K. Lo ◽  
M. Nagpal ◽  
H. Maisel
Keyword(s):  
Fibre Cell ◽  
Lens Fibre ◽  
Lens Fibre Cell

scholarly journals Transcriptomic analysis and novel insights into lens fibre cell differentiation regulated by Gata3

Open Biology ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 190220
Author(s):  
Elena Martynova ◽  
Yilin Zhao ◽  
Qing Xie ◽  
Deyou Zheng ◽  
Ales Cvekl
Keyword(s):  
Cell Differentiation ◽  
Transcriptional Control ◽  
Kinase Inhibitors ◽  
Neuroendocrine Cells ◽  
Intermediate Filament Protein ◽  
Loss Of Function ◽  
Fibre Cell ◽  
Lens Fibre ◽  
Lens Fibre Cell

Gata3 is a DNA-binding transcription factor involved in cellular differentiation in a variety of tissues including inner ear, hair follicle, kidney, mammary gland and T-cells. In a previous study in 2009, Maeda et al . ( Dev. Dyn. 238 , 2280–2291; doi:10.1002/dvdy.22035 ) found that Gata3 mutants could be rescued from midgestational lethality by the expression of a Gata3 transgene in sympathoadrenal neuroendocrine cells. The rescued embryos clearly showed multiple defects in lens fibre cell differentiation. To determine whether these defects were truly due to the loss of Gata3 expression in the lens, we generated a lens-specific Gata3 loss-of-function model. Analogous to the previous findings, our Gata3 null embryos showed abnormal regulation of cell cycle exit during lens fibre cell differentiation, marked by reduction in the expression of the cyclin-dependent kinase inhibitors Cdkn1b/p27 and Cdkn1c/p57, and the retention of nuclei accompanied by downregulation of Dnase IIβ. Comparisons of transcriptomes between control and mutated lenses by RNA-Seq revealed dysregulation of lens-specific crystallin genes and intermediate filament protein Bfsp2. Both Cdkn1b/p27 and Cdkn1c/p57 loci are occupied in vivo by Gata3, as well as Prox1 and c-Jun, in lens chromatin. Collectively, our studies suggest that Gata3 regulates lens differentiation through the direct regulation of the Cdkn1b/p27and Cdkn1c/p57 expression, and the direct/or indirect transcriptional control of Bfsp2 and Dnase IIβ.

The influence of Lyn kinase on Na,K-ATPase in porcine lens epithelium

2004 ◽  
Vol 286 (1) ◽  
pp. C90-C96 ◽  
Author(s):  
Larry D. Bozulic ◽  
William L. Dean ◽  
Nicholas A. Delamere
Keyword(s):  
Atpase Activity ◽  
Western Blot ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Tyrosine Phosphatase ◽  
Lens Epithelium ◽  
Membrane Material ◽  
Lyn Kinase ◽  
Multiple Protein ◽  
Lens Cells

Na,K-ATPase is essential for the regulation of cytoplasmic Na+and K+levels in lens cells. Studies on the intact lens suggest activation of tyrosine kinases may inhibit Na,K-ATPase function. Here, we tested the influence of Lyn kinase, a Src-family member, on tyrosine phosphorylation and Na,K-ATPase activity in membrane material isolated from porcine lens epithelium. Western blot studies indicated the expression of Lyn in lens cells. When membrane material was incubated in ATP-containing solution containing partially purified Lyn kinase, Na,K-ATPase activity was reduced by ∼38%. Lyn caused tyrosine phosphorylation of multiple protein bands. Immunoprecipitation and Western blot analysis showed Lyn treatment causes an increase in density of a 100-kDa phosphotyrosine band immunopositive for Na,K-ATPase α1polypeptide. Incubation with protein tyrosine phosphatase 1B (PTP-1B) reversed the Lyn-dependent tyrosine phosphorylation increase and the change of Na,K-ATPase activity. The results suggest that Lyn kinase treatment of a lens epithelium membrane preparation is able to bring about partial inhibition of Na,K-ATPase activity associated with tyrosine phosphorylation of multiple membrane proteins, including the Na,K-ATPase α1catalytic subunit.

Insulin and IGF-I Affect the Protein Composition of the Lens Fibre Cell with Possible Consequences for Cataract

2000 ◽  
Vol 70 (6) ◽  
pp. 785-794 ◽  
Author(s):  
Azem Civil ◽  
Siebe T van Genesen ◽  
Erik Jan Klok ◽  
Nicolette H Lubsen
Keyword(s):  
Protein Composition ◽  
Fibre Cell ◽  
Lens Fibre ◽  
Igf I ◽  
Lens Fibre Cell
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