Publication: Complex I function is defective in complex IV-deficient Caenorhabditis elegans
Issued Date
2009-03-06
Resource Type
ISSN
1083351X
00219258
00219258
Other identifier(s)
2-s2.0-65249189438
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Mahidol University
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SCOPUS
Bibliographic Citation
Journal of Biological Chemistry. Vol.284, No.10 (2009), 6425-6435
Suggested Citation
Wichit Suthammarak, Yu Ying Yang, Phil G. Morgan, Margaret M. Sedensky Complex I function is defective in complex IV-deficient Caenorhabditis elegans. Journal of Biological Chemistry. Vol.284, No.10 (2009), 6425-6435. doi:10.1074/jbc.M805733200 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/27269
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Title
Complex I function is defective in complex IV-deficient Caenorhabditis elegans
Abstract
Cytochrome c oxidase (COX) is hypothesized to be an important regulator of oxidative phosphorylation. However, no animal phenotypes have been described due to genetic defects in nuclear-encoded subunits of COX.Weknocked down predicted homologues of COX IV and COX Va in the nematode Caenorhabditis elegans. Animals treated with W09C5.8 (COX IV) or Y37D8A.14 (COX Va) RNA interference had shortened lifespans and severe defects in mitochondrial respiratory chain function. Amount and activity of complex IV, as well as supercomplexes that included complex IV, were decreased in COXdeficient worms. The formation of supercomplex I:III was not dependent on COX. We found that COX deficiencies decreased intrinsic complex I enzymatic activity, as well as complex I-III enzymatic activity. However, overall amounts of complex I were not decreased in these animals. Surprisingly, intrinsic complex I enzymatic activity is dependent on the presence of complex IV, despite no overall decrease in the amount of complex I. Presumably the association of complex I with complex IV within the supercomplex I:III:IV enhances electron flow through complex I. Our results indicate that reduction of a single subunit within the electron transport chain can affect multiple enzymatic steps of electron transfer, including movement within a different protein complex. Patients presenting with multiple defects of electron transport may, in fact, harbor a single genetic defect. © 2009 by The American Society for Biochemistry and Molecular Biology, Inc.