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Updated: Jun 26, 2026

Characterization of Molecular Mechanisms of In vivo UVR Induced Cataract
Published on: November 28, 2012
Mechanism of cataract formation in alphaA-crystallin Y118D mutation
Qingling Huang1, Linlin Ding, Kim B Phan
1Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California 90095, USA.
Purpose:
The aim of this study was to elucidate the molecular mechanisms that lead to a dominant nuclear cataract in a mouse harboring the Y118D mutation in the alphaA-crystallin gene.
Methods:
The physicochemical properties of alpha-crystallin obtained from mouse lenses with the Y118D mutation as well as a recombinant Y118D alphaA-crystallin were studied using gel filtration, two-dimensional (2D) gel electrophoresis, multi-angle light scattering, circular dichroism, fluorescence, and chaperone activities.
Results:
Both native alpha-crystallin from mutant lens and recombinant alphaA-Y118D displayed higher molecular mass distribution than the wild-type. Circular dichroism spectra indicated changes in the secondary structures of alphaA-Y118D. The alphaA-Y118D protein prevented nonspecific protein aggregation more effectively than wild-type alphaA-crystallin. The gel filtration and 2D gel electrophoresis analysis showed a significant reduction of Y118D mutant protein in comparison with wild-type alphaA protein of heterozygous mutant lenses. Quantitative RT-PCR results confirmed a decrease in alphaA and alphaB transcripts in the homozygous mutant alpha A(Y118D/Y118D) lenses.
Conclusions:
The alphaA-Y118D mutant protein itself displays an increased chaperone-like activity. However, the dominant nuclear cataract is associated with a significant decrease in the amount of alphaA-crystallin, leading to a reduction in total chaperone capacity needed for maintaining lens transparency.
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