An Increase in Phosphorylation and Truncation of Crystallin With the Progression of Cataracts

Abstract

BackgroundCataracts are the leading cause of blindness worldwide; however, there is no evidence regarding the direct formation of cataracts. At present, there is no treatment method other than surgery to prevent the formation or progression of cataracts.ObjectiveUnderstanding the protein changes during various stages of cataracts might help realize the mechanism of the formation and progression of cataracts.MethodsLens materials were collected from cataract surgery. Cataracts were classified according to lens opacity using the gradation of the Lens Opacities Classification System. Lens proteins were separated by 2-dimensional polyacrylamide gel electrophoresis. Protein spots were visualized by Coomassie blue staining, and expression patterns were analyzed. Protein spots of interest were excised from 2-dimensional polyacrylamide gel electrophoresis gels, digested in situ with trypsin, and analyzed by mass spectrometry and liquid chromatographic tandem mass spectrometry.ResultsCrystallin was the major protein in the cataract lens, and αA, βB1, αB, and βA4 were the dominant types. Crystallin αB and βA4 increased with the formation of lens opacity. Moreover, phosphorylation and truncation of these proteins increased with the progression of cataracts.ConclusionCrystallin αB and βA4 and phosphorylation and truncation of crystallin in the lens might contribute to the formation of cataracts. In contrast, acetylation was not dominant in the progression of cataracts and did not play major role in the formation of cataracts.

Glyphosate pathways to modern diseases V: Amino acid analogue of glycine in diverse proteins

“…An increase in phosphorylation of crystallin is linked to increased cataract risk [215]. Such an increase can be expected in the context of hyperactive kinases and inhibited phosphatases, such as is expected with glyphosate insertion in place of glycine in these molecules.…”

Lens Cytoskeleton: An Update on the Etiopathogenesis of Human Cataracts

“…Moreover, truncated bB1 crystallin, trimmed of N-terminal residues, interacts abnormally compared to the native form, and it is suggested that since truncation occurs extensively in the aging human lens, it may be an important factor for age-related cataract formation [ 19 ]. In a recent study, it was shown that αB- and βA4- crystallin were upregulated with the loss of lens transparency and that truncation of those specific crystallins increased as the lens opacification advanced [ 13 , 20 , 21 ]. Other lens proteins that are truncated with age include connexins and cytoskeletal proteins [ 22 ].…”

Photosensitizing Activity of Endogenous Eye Lens Chromophores: An Attempt to Unravel Their Contributions to Photo‐Aging and Cataract Disease

“…The analysis of human eye lens proteins from cataractous subjects has demonstrated the presence of numerous post‐translational modifications, such as deamination, glycation, oxidation, truncation, and others . Paradoxically, some of the main protecting agents, ascorbate and the UV filters derived from tryptophan catabolism that are found in relatively high concentrations in the eye lens can participate in reactions with nucleophilic amino acids, giving rise to these protein modifications .…”