Publications by authors named "Aura T Chavez Zobel"

Mutations in the alpha-crystallin domain of 4 of the small heat shock proteins (sHsp) (Hsp27/HspB1, alphaA-crystallin/ HspB4, alphaB-crystallin/HspB5, and HspB8) are responsible for dominant inherited diseases in humans. One such mutation at a highly conserved arginine residue was shown to cause major conformational defects and intracellular aggregation of alphaA- and alphaB-crystallins and HspB8. Here, we studied the effect of this Arg mutation on the structure and function of Hsp27.

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The family of small heat shock proteins (sHsp) is composed of 10 members in mammals, four of which are found mutated in diseases associated with the accumulation of protein aggregates. Though many sHsp have demonstrated molecular chaperone activity in vitro in cell-free conditions, their activity in vivo in the normal cellular context remains unclear. In the present study, we investigated the capacity of the sHsp, HspB8/Hsp22, to prevent protein aggregation in the cells using the polyglutamine protein Htt43Q as a model.

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Hsp27 is expressed at high levels after mild heat shock and contributes to making cells extremely resistant to subsequent treatments. The activity of the protein is regulated at the transcriptional level, but also by phosphorylation, which occurs rapidly during stress and is responsible for causing the dissociation of large 700-kDa Hsp27 oligomers into dimers. We investigated the mechanism by which phosphorylation and oligomerization modulate the protective activity of Chinese hamster Hsp27.

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A familial form of desmin-related myopathy (DRM) is associated with a missense mutation (R120G) in alphaB-crystallin (alphaB) and is characterized by intracellular desmin aggregation. Because alphaB is a molecular chaperone that participates in the assembly of desmin filaments, it has been suggested that the desmin aggregation might be due to the loss of alphaB function. We report here that alphaBR120G has indeed impaired in vivo function and structure as reflected by a highly reduced capacity to protect cells against heat shock and by an abnormal supramolecular organization even in cells not expressing desmin.

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