Precipitation of crystallins from young rat lens by endogenous calpain

T. R. Shearer, M. Shih, M. Azuma, L. L. David

Research output: Contribution to journalArticle

36 Scopus citations

Abstract

The purpose of these experiments was to study the mechanism for precipitation of lens crystallins in cataract. An in vitro model was developed to activate the endogenous protease calpain II in the soluble proteins from young rat lens by addition of calcium in the presence of 120 mm KCl. Light-scattering, insoluble proteins were produced approximately 4-6 days after calpain II activation. Results showed that proteolysis was caused by activation of lens calpain II, proteolysis preceded precipitation by several days, and α-crystallin acted as a molecular chaperone against precipitation of crystallins caused by proteolysis. These data supported our hypothesis that calpain-induced proteolysis of the N-terminal arms of β-crystallin polypeptides leads to a loss of normal oligomerization of β-crystallin polypeptides and formation of abnormal insoluble aggregates, possibly stabilized by hydrophobic interactions.

Original languageEnglish (US)
Pages (from-to)141-150
Number of pages10
JournalExperimental Eye Research
Volume61
Issue number2
DOIs
StatePublished - Aug 1995

Keywords

  • Calpain
  • Cataract
  • Crystallins
  • Insolubilization
  • Lens
  • Light scatter
  • Proteolysis
  • Rat

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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