Inactivation of parkin by oxidative stress and C-terminal truncations: a protective role of molecular chaperones.
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.
Winklhofer
Konstanze F
KF
Department of Cellular Biochemistry, Max-Planck-Institute for Biochemistry, D-82152 Martinsried, Germany. winklhof@biochem.mpg.de
Henn
Iris H
IH
Kay-Jackson
Penelope C
PC
Heller
Ulrich
U
Tatzelt
Jörg
J
D002460:Cell Line; D019281:Dimerization; D004789:Enzyme Activation; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism / Q000502:physiology; D006801:Humans; D018832:Molecular Chaperones / Q000502:physiology; D018384:Oxidative Stress; D017510:Protein Folding; D017384:Sequence Deletion; D013696:Temperature; D014162:Transfection; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
D018840:HSP70 Heat-Shock Proteins; D018832:Molecular Chaperones; D044767:Ubiquitin-Protein Ligases; C111567:parkin protein