title: An increase in phosphorylation and truncation of crystallin with the progression of cataracts.
abstract: BACKGROUND
  Cataracts 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.
  
  
  OBJECTIVE
  Understanding the protein changes during various stages of cataracts might help realize the mechanism of the formation and progression of cataracts.
  
  
  METHODS
  Lens 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.
  
  
  RESULTS
  Crystallin 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.
  
  
  CONCLUSIONS
  Crystallin 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.
authors.affiliation: Department of Ophthalmology, China Medical University Hospital, Taichung, Taiwan ; Department of Medical Science, China Medical University Hospital, Taichung, Taiwan ; Department of Chinese Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Hui-Ju
authors.initials: HJ
authors.lastname: Lin
authors.affiliation: Department of Medical Science, China Medical University Hospital, Taichung, Taiwan ; Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan.
authors.forename: Chien-Chen
authors.initials: CC
authors.lastname: Lai
authors.affiliation: Department of Medical Science, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Shiuan-Yi
authors.initials: SY
authors.lastname: Huang
authors.affiliation: Department of Medical Science, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Wei-Yi
authors.initials: WY
authors.lastname: Hsu
authors.affiliation: Department of Medical Science, China Medical University Hospital, Taichung, Taiwan ; Department of Chinese Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Fuu-Jen
authors.initials: FJ
authors.lastname: Tsai
keywords: cataract; crystallin; mass spectrometry; phosphorylation; truncation