April 1999
Volume 40, Issue 5
Free
Articles  |   April 1999
AlphaB-crystallin selectively targets intermediate filament proteins during thermal stress.
Author Affiliations
  • P J Muchowski
    Department of Biological Structure, University of Washington, Seattle 98195-7420, USA.
  • M M Valdez
    Department of Biological Structure, University of Washington, Seattle 98195-7420, USA.
  • J I Clark
    Department of Biological Structure, University of Washington, Seattle 98195-7420, USA.
Investigative Ophthalmology & Visual Science April 1999, Vol.40, 951-958. doi:
  • Views
  • PDF
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      P J Muchowski, M M Valdez, J I Clark; AlphaB-crystallin selectively targets intermediate filament proteins during thermal stress.. Invest. Ophthalmol. Vis. Sci. 1999;40(5):951-958.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

PURPOSE: AlphaB-Crystallin is a small heat shock protein (sHsp) expressed at high levels in the lens of the eye, where its molecular chaperone functions may protect against cataract formation in vivo. The purpose of this study was to identify protein targets for the sHsp alphaB-crystallin in lens cell homogenates during conditions of mild thermal stress. METHODS: The authors report the use of a fusion protein, maltose-binding protein alphaB-crystallin (MBP-alphaB), immobilized on amylose resin as a novel method for isolating endogenous alphaB-crystallin-binding proteins from lens cell homogenates after mild thermal stress. RESULTS: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and western immunoblot analyses showed selective interactions in lens cell homogenates between MBP-alphaB and endogenous alphaA- and alphaB-crystallins, the lens-specific intermediate filament proteins phakinin (CP49) and filensin (CP115), and vimentin during a mild 20-minute heat shock at 45 degrees C. No interactions were observed with the beta- or gamma-crystallins, or the cytoskeletal proteins actin, alpha-tubulin, and spectrin, although these proteins were present in lens cell homogenates. In contrast, gamma-crystallin and actin interacted with MBP-alphaB at 45 degrees C only in their purified states. The results obtained with MBP-alphaB were confirmed by immunoprecipitation reactions in which immunoprecipitation of native bovine alphaB-crystallin from heat-shocked lens cell homogenates resulted in the coprecipitation of phakinin and filensin. CONCLUSIONS: In the lens the sHsp alphaB-crystallin may selectively target intermediate filaments for protection against unfolding during conditions of stress.

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×