Inactivation of parkin by oxidative stress and C-terminal truncations: a protective role of molecular chaperones |
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Authors: | Winklhofer Konstanze F Henn Iris H Kay-Jackson Penelope C Heller Ulrich Tatzelt Jörg |
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Affiliation: | Department of Cellular Biochemistry, Max-Planck-Institute for Biochemistry, D-82152 Martinsried, Germany. winklhof@biochem.mpg.de |
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Abstract: | Loss of parkin function is linked to autosomal recessive juvenile parkinsonism. Here we show that proteotoxic stress and short C-terminal truncations induce misfolding of parkin. As a consequence, wild-type parkin was depleted from a high molecular weight complex and inactivated by aggregation. Similarly, the pathogenic parkin mutant W453Stop, characterized by a C-terminal deletion of 13 amino acids, spontaneously adopted a misfolded conformation. Mutational analysis indicated that C-terminal truncations exceeding 3 amino acids abolished formation of detergent-soluble parkin. In the cytosol scattered aggregates of misfolded parkin contained the molecular chaperone Hsp70. Moreover, increased expression of chaperones prevented aggregation of wild-type parkin and promoted folding of the W453Stop mutant. Analyzing parkin folding in vitro indicated that parkin is aggregation-prone and that its folding is dependent on chaperones. Our study demonstrates that C-terminal truncations impede parkin folding and reveal a new mechanism for inactivation of parkin. |
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