Tissue localization and solubilities of αA-crystallin and its numerous C-terminal truncation products in pre- and postcataractous ICR/f rat lenses.

Academic Article

Abstract

  • PURPOSE: To investigate the tissue distribution and solubilities of various αA-crystallin truncation products in the cataractous ICR/f rat model. METHODS: Rat lenses from precataractous (21-day) and postcataractous (100-day) ICR/f rats were sectioned and applied to a matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) target plate. Mass spectrometry images were collected to obtain a macromolecular profile of the abundant lens proteins. Separately, age-matched lenses were extracted into water-soluble (WS) and water-insoluble/urea-soluble (WI-US) fractions and subjected to MALDI-TOF mass spectrometry to correlate the protein solubilities with the imaging data. Protein identities were assigned by using a top-down proteomics approach on a high-resolution mass spectrometer. RESULTS: Ten novel αA-crystallin truncation products were identified, along with six previously known αA-crystallin truncation products. Nearly all truncations exhibited nuclear localization, with larger truncated products displaying a ringlike localization that progressed outward toward the extranuclear, cortical region. The distributions were similar in both ages with the only significant difference being the amount of tissue area encompassed by a particular species with increasing age. Almost all nuclear products fractionated into the WI-US fraction, whereas the five largest extranuclear species exhibited mixed solubility. CONCLUSIONS: A successful methodology for the sectioning and imaging of pre- and postcataractous ICR/f rat lenses has been established. Data collected from these analyses indicate that there are multiple αA-crystallin truncation products present in both pre- and postcataractous rats. Furthermore, these species have defined lenticular localizations and unique solubilities that may be a consequence of lens development and protein function within the lens environment.
  • Keywords

  • Animals, Cataract, Chromatography, High Pressure Liquid, Disease Models, Animal, Fourier Analysis, Lens, Crystalline, Peptide Fragments, Proteomics, Rats, Rats, Wistar, Solubility, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Tissue Distribution, alpha-Crystallin A Chain
  • Digital Object Identifier (doi)

    Author List

  • Stella DR; Floyd KA; Grey AC; Renfrow MB; Schey KL; Barnes S
  • Start Page

  • 5153
  • End Page

  • 5161
  • Volume

  • 51
  • Issue

  • 10