The C8ORF38 homologue Sicily is a cytosolic chaperone for a mitochondrial complex I subunit |
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Authors: | Ke Zhang Zhihong Li Manish Jaiswal Vafa Bayat Bo Xiong Hector Sandoval Wu-Lin Charng Gabriela David Claire Haueter Shinya Yamamoto Brett H Graham Hugo J Bellen |
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Institution: | 1.Program in Structural and Computational Biology and Molecular Biophysics, 2.Department of Molecular and Human Genetics, 3.Howard Hughes Medical Institute, 4.Program in Developmental Biology, 5.Medical Scientist Training Program, 6.Department of Neuroscience, and 7.Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030 |
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Abstract: | Mitochondrial complex I (CI) is an essential component in energy production through oxidative phosphorylation. Most CI subunits are encoded by nuclear genes, translated in the cytoplasm, and imported into mitochondria. Upon entry, they are embedded into the mitochondrial inner membrane. How these membrane-associated proteins cope with the hydrophilic cytoplasmic environment before import is unknown. In a forward genetic screen to identify genes that cause neurodegeneration, we identified sicily, the Drosophila melanogaster homologue of human C8ORF38, the loss of which causes Leigh syndrome. We show that in the cytoplasm, Sicily preprotein interacts with cytosolic Hsp90 to chaperone the CI subunit, ND42, before mitochondrial import. Loss of Sicily leads to loss of CI proteins and preproteins in both mitochondria and cytoplasm, respectively, and causes a CI deficiency and neurodegeneration. Our data indicate that cytosolic chaperones are required for the subcellular transport of ND42. |
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