Mitochondrial ATP synthase, ADP/ATP translocase (ANT), and inorganic phosphate carrier (PiC) are supposed to form a supercomplex called ATP synthasome. Our protein and transcript analysis of rat tissues indicates that the expression of ANT and PiC is transcriptionally controlled in accordance with the biogenesis of ATP synthase. In contrast, the content of ANT and PiC is increased in ATP synthase deficient patients' fibroblasts, likely due to a post-transcriptional adaptive mechanism. A structural analysis of rat heart mitochondria by immunoprecipitation, blue native/SDS electrophoresis, immunodetection and MS analysis revealed the presence of ATP synthasome. However, the majority of PiC and especially ANT did not associate with ATP synthase, suggesting that most of PiC, ANT and ATP synthase exist as separate entities.
- MeSH
- adenosintrifosfát biosyntéza MeSH
- fibroblasty metabolismus MeSH
- fosfáty chemie metabolismus MeSH
- krysa rodu rattus MeSH
- kultivované buňky MeSH
- lidé MeSH
- makromolekulární látky chemie metabolismus MeSH
- mitochondriální ADP/ATP-translokasy chemie genetika metabolismus MeSH
- mitochondriální protonové ATPasy chemie genetika metabolismus MeSH
- mitochondrie metabolismus MeSH
- novorozená zvířata MeSH
- potkani Wistar MeSH
- srdeční mitochondrie metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The highly conserved ADP/ATP carrier (AAC) is a key energetic link between the mitochondrial (mt) and cytosolic compartments of all aerobic eukaryotic cells, as it exchanges the ATP generated inside the organelle for the cytosolic ADP. Trypanosoma brucei, a parasitic protist of medical and veterinary importance, possesses a single functional AAC protein (TbAAC) that is related to the human and yeast ADP/ATP carriers. However, unlike previous studies performed with these model organisms, this study showed that TbAAC is most likely not a stable component of either the respiratory supercomplex III+IV or the ATP synthasome but rather functions as a physically separate entity in this highly diverged eukaryote. Therefore, TbAAC RNA interference (RNAi) ablation in the insect stage of T. brucei does not impair the activity or arrangement of the respiratory chain complexes. Nevertheless, RNAi silencing of TbAAC caused a severe growth defect that coincides with a significant reduction of mt ATP synthesis by both substrate and oxidative phosphorylation. Furthermore, TbAAC downregulation resulted in a decreased level of cytosolic ATP, a higher mt membrane potential, an elevated amount of reactive oxygen species, and a reduced consumption of oxygen in the mitochondria. Interestingly, while TbAAC has previously been demonstrated to serve as the sole ADP/ATP carrier for ADP influx into the mitochondria, our data suggest that a second carrier for ATP influx may be present and active in the T. brucei mitochondrion. Overall, this study provides more insight into the delicate balance of the functional relationship between TbAAC and the oxidative phosphorylation (OXPHOS) pathway in an early diverged eukaryote.
- MeSH
- mitochondriální ADP/ATP-translokasy chemie genetika metabolismus MeSH
- molekulární evoluce * MeSH
- oxidativní fosforylace * MeSH
- protozoální proteiny chemie genetika metabolismus MeSH
- Trypanosoma brucei brucei genetika metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
