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Clusterin has chaperone-like activity similar to that of small heat shock proteins

Journal Article


Abstract


  • Clusterin is a highly conserved protein which is expressed at increased levels by many cell types in response to a broad variety of stress conditions. A genuine physiological function for clusterin has not yet been established. The results presented here demonstrate for the first time that clusterin has chaperone-like activity. At physiological concentrations, clusterin potently protected glutathione S-transferase and catalase from heat-induced precipitation and α-lactalbumin and bovine serum albumin from precipitation induced by reduction with dithiothreitol. Enzyme-linked immunosorbent assay data showed that clusterin bound preferentially to heat- stressed glutathione S-transferase and to dithiothreitol-treated bovine serum albumin and α-lactalbumin. Size exclusion chromatography and SDS- polyacrylamide gel electrophoresis analyses showed that clusterin formed high molecular weight complexes (HMW) with all four proteins tested. Small heat shock proteins (sHSP) also act in this way to prevent protein precipitation and protect cells from heat and other stresses. The stoichiometric subunit molar ratios of clusterin:stressed protein during formation of HMW complexes (which for the four proteins tested ranged from 1.0:1.3 to 1.0:11) is less than the reported ratios for sHSP-mediated formation of HMW complexes (1.0:1.0 or greater), indicating that clusterin is a very efficient chaperone. Our results suggest that clusterin may play a sHSP-like role in cytoprotection.

Publication Date


  • 1999

Citation


  • Humphreys, D. T., Carver, J. A., Easterbrook-Smith, S. B., & Wilson, M. R. (1999). Clusterin has chaperone-like activity similar to that of small heat shock proteins. Journal of Biological Chemistry, 274(11), 6875-6881. doi:10.1074/jbc.274.11.6875

Scopus Eid


  • 2-s2.0-0033548566

Start Page


  • 6875

End Page


  • 6881

Volume


  • 274

Issue


  • 11

Abstract


  • Clusterin is a highly conserved protein which is expressed at increased levels by many cell types in response to a broad variety of stress conditions. A genuine physiological function for clusterin has not yet been established. The results presented here demonstrate for the first time that clusterin has chaperone-like activity. At physiological concentrations, clusterin potently protected glutathione S-transferase and catalase from heat-induced precipitation and α-lactalbumin and bovine serum albumin from precipitation induced by reduction with dithiothreitol. Enzyme-linked immunosorbent assay data showed that clusterin bound preferentially to heat- stressed glutathione S-transferase and to dithiothreitol-treated bovine serum albumin and α-lactalbumin. Size exclusion chromatography and SDS- polyacrylamide gel electrophoresis analyses showed that clusterin formed high molecular weight complexes (HMW) with all four proteins tested. Small heat shock proteins (sHSP) also act in this way to prevent protein precipitation and protect cells from heat and other stresses. The stoichiometric subunit molar ratios of clusterin:stressed protein during formation of HMW complexes (which for the four proteins tested ranged from 1.0:1.3 to 1.0:11) is less than the reported ratios for sHSP-mediated formation of HMW complexes (1.0:1.0 or greater), indicating that clusterin is a very efficient chaperone. Our results suggest that clusterin may play a sHSP-like role in cytoprotection.

Publication Date


  • 1999

Citation


  • Humphreys, D. T., Carver, J. A., Easterbrook-Smith, S. B., & Wilson, M. R. (1999). Clusterin has chaperone-like activity similar to that of small heat shock proteins. Journal of Biological Chemistry, 274(11), 6875-6881. doi:10.1074/jbc.274.11.6875

Scopus Eid


  • 2-s2.0-0033548566

Start Page


  • 6875

End Page


  • 6881

Volume


  • 274

Issue


  • 11