Parkin negatively regulates JNK pathway in the dopaminergic neurons of Drosophila.
Parkin, an E3 ubiquitin ligase, has been found to be responsible for autosomal recessive juvenile parkinsonism characterized primarily by selective loss of dopaminergic neurons with subsequent defects in movements. However, the molecular mechanisms underlying this neuron loss remain elusive. Here, we characterized Drosophila parkin loss-of-function mutants, which exhibit shrinkage of dopaminergic neurons with decreased tyrosine hydroxylase level and impaired locomotion. The behavioral defect of parkin mutant flies was partially restored by administering L-DOPA, and the dopamine level in the brains of parkin mutant flies was highly decreased. Intriguingly, we found that c-Jun N-terminal kinase (JNK) is strongly activated in the dopaminergic neurons of parkin mutants and that impaired dopaminergic neuron phenotypes are dependent on the activation of the JNK signaling pathway. In consistent with this, our epistatic analysis and mammalian cell studies showed that Parkin inhibits the JNK signaling pathway in an E3 activity-dependent manner. These results suggest that loss of Parkin function up-regulates the JNK signaling pathway, which may contribute to the vulnerability of dopaminergic neurons in Drosophila parkin mutants and perhaps autosomal recessive juvenile parkinsonism patients.
Cha
Guang-Ho
GH
National Creative Research Initiatives Center for Cell Growth Regulation, and Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong, Yusong-gu, Taejon 305-701, Korea.
Kim
Sunhong
S
Park
Jeehye
J
Lee
Eunji
E
Kim
Myungjin
M
Lee
Sung Bae
SB
Kim
Jin Man
JM
Chung
Jongkyeong
J
Cho
Kyoung Sang
KS
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism*; D019556:COS Cells; D002522:Chlorocebus aethiops; D004298:Dopamine / Q000378:metabolism; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D006651:Histocytochemistry; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D007980:Levodopa; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009474:Neurons / Q000378:metabolism*; D020734:Parkinsonian Disorders / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases
D029721:Drosophila Proteins; D007980:Levodopa; D014446:Tyrosine 3-Monooxygenase; D044767:Ubiquitin-Protein Ligases; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; C487430:park protein, Drosophila; D004298:Dopamine