Human Mitochondrial Cytochrome b Variants Studied in Yeast: Not All Are Silent Polymorphisms.
Variations in mitochondrial DNA (mtDNA) cytochrome b (mt-cyb) are frequently found within the healthy population, but also occur within a spectrum of mitochondrial and common diseases. mt-cyb encodes the core subunit (MT-CYB) of complex III, a central component of the oxidative phosphorylation system that drives cellular energy production and homeostasis. Despite significant efforts, most mt-cyb variations identified are not matched with corresponding biochemical data, so their functional and pathogenic consequences in humans remain elusive. While human mtDNA is recalcitrant to genetic manipulation, it is possible to introduce human-associated point mutations into yeast mtDNA. Using this system, we reveal direct links between human mt-cyb variations in key catalytic domains of MT-CYB and significant changes to complex III activity or drug sensitivity. Strikingly, m.15257G>A (p.Asp171Asn) increased the sensitivity of yeast to the antimalarial drug atovaquone, and m.14798T>C (p.Phe18Leu) enhanced the sensitivity of yeast to the antidepressant drug clomipramine. We demonstrate that while a small number of mt-cyb variations had no functional effect, others have the capacity to alter complex III properties, suggesting they could play a wider role in human health and disease than previously thought. This compendium of new mt-cyb-biochemical relationships in yeast provides a resource for future investigations in humans.
Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, Cedex, 91198, France.
Zehua
Z
Song
Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, Cedex, 91198, France.
Anaïs
A
Laleve
Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, Cedex, 91198, France.
Cindy
C
Vallières
Molecular Biophysics Laboratories, Institute of Biomedical and Biomolecular Science, School of Biological Sciences, University of Portsmouth, Portsmouth, UK.
John E
JE
McGeehan
Brain Tumour Research Centre, Institute of Biomedical and Biomolecular Science, School of Pharmacy and Biomedicine, University of Portsmouth, Portsmouth, UK.
Rhiannon E
RE
Lloyd
Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, Cedex, 91198, France.
Brigitte
B
Meunier
D000929:Antidepressive Agents, Tricyclic / Q000494:pharmacology; D000962:Antimalarials / Q000494:pharmacology; D053626:Atovaquone / Q000494:pharmacology; D020134:Catalytic Domain; D002997:Clomipramine / Q000494:pharmacology; D003001:Cloning, Molecular; D045303:Cytochromes b / Q000737:chemistry / Q000235:genetics*; D004271:DNA, Fungal / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D014450:Electron Transport Complex III / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D017354:Point Mutation; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics
D000929:Antidepressive Agents, Tricyclic; D000962:Antimalarials; D004271:DNA, Fungal; D004272:DNA, Mitochondrial; D029701:Saccharomyces cerevisiae Proteins; D045303:Cytochromes b; D014450:Electron Transport Complex III; D002997:Clomipramine; D053626:Atovaquone
MT-CYB; atovaquone; clomipramine; mitochondrial DNA; yeast model