BACKGROUND Mutation in αA-crystallin contributes to the development of congenital cataract in humans. Heterooligomerization of αA-crystallin and αB-crystallin is essential for maintaining transparency in the eye lens. The effect of congenital cataract causing mutants of αA-crystallin on subunit exchange and interaction with αB-crystallin is unknown. In the present study, interaction of the muta...

PURPOSE To develop a general tissue preparation protocol for MALDI (Matrix-Assisted Laser Desorption Ionization) imaging mass spectrometry of ocular lens tissue, and to compare the spatial distributions of alpha-crystallin and its modified forms in bovine and rabbit lenses. METHODS Frozen bovine and rabbit lenses were cryosectioned equatorially at -20 degrees C into 12 microm-thick tissue sec...

Mutation of the glycine 98 residue to arginine in alphaA-crystallin has been shown to cause presenile cataract in an Indian family. Our earlier study showed that the mutant protein exhibits folding defects that lead to aggregation and inclusion body formation in Escherichia coli. Despite the presence of a normal copy, the pathology is seen in the heterozygous individuals. Formation of mixed oli...

PURPOSE S-glutathiolated proteins are formed in the lens during aging and cataractogenesis. The objective of this work was to explore the role of the ubiquitin-proteasome pathway in eliminating S-glutathiolated gammaC-crystallin. METHODS Recombinant human gammaC-crystallin was mixed with various concentrations of glutathione (GSH) and diamide at 25 degrees C for 1 hour. The extent of glutathi...

Emerging evidence suggests molecular chaperones have a role in the pathogenesis of obesity and diabetes. As αB-crystallin and HspB2 are molecular chaperones and data suggests their expression is elevated in the skeletal muscle of diabetic and obese animals, we sought to determine if αB-crystallin and HspB2 collectively play a functional role in the metabolic phenotype of diet-induced obesity. U...

PURPOSE The aim of this study was to identify glucocorticoid induced cataracts (GIC)-specific modified water insoluble-urea soluble (WI-US) crystallins and related changes after rat lens were exposed to dexamethasone (Dex). METHODS We separated WI-US lens proteins by two-dimensional electrophoresis (2-DE). The crystallins were then analyzed with matrix assisted laser desorption/ionization tim...

alpha-Crystallin has been shown to function as a molecular chaperone in preventing thermal aggregation of crystallins and other proteins. The molecular mechanism of this protection is not yet clear. gamma-Crystallin aggregates upon exposure to UV light. We have investigated the effect of the presence of alpha-crystallin in the photoaggregation process and find that alpha-crystallin does not pre...

CONCLUSIONS. Bovine lens -crystallin in solution can be modeled as a fenestrated spherical shell of diameter 169 Å. At physiological temperatures, a weak interaction between and -crystallin occurs, and -crystallin is located in the fenestrations. Deuterium substitution indicates that the superaggregation process is controlled by hydrogen bonding. However, the chaperone process and superaggregat...

In the calf eye lens, four morphologically distinct cell types can be detected: three in the epithelial monolayer and one in the cortical part. During differentiation, there is a quantitative change in the synthesis of crystallin subunits. A marked increase in alphaA-chains and several beta-crystallin polypeptides accompanies the transition from epithelial to fiberlike lens cells while synthesi...

PURPOSE Oxidative stress and other forms of injury to trabecular meshwork (TM) cells may contribute to changes seen with age and primary open-angle glaucoma. This study was designed to investigate if TM expresses alpha B-crystallin, a small heat-shock protein with chaperone activity, and whether it might be overexpressed under stress conditions. METHODS The TM from human and monkey eyes, as w...