التفاصيل البيبلوغرافية
| العنوان: |
High-Conductance Channel Formation in Yeast Mitochondria is Mediated by F-ATP Synthase e and g Subunits. |
| المؤلفون: |
Carraro, Michela, Checchetto, Vanessa, Sartori, Geppo, Kucharczyk, Roz, di Rago, Jean-Paul, Minervini, Giovanni, Franchin, Cinzia, Arrigoni, Giorgio, Giorgio, Valentina, Petronilli, Valeria, Tosatto, Silvio C. E., Lippe, Giovanna, Szabó, Ildikó, Bernardi, Paolo |
| المصدر: |
Cellular Physiology & Biochemistry (Karger AG); Nov2018, Vol. 50 Issue 5, p1840-1855, 16p |
| مصطلحات موضوعية: |
MITOCHONDRIA, MEMBRANE permeability (Biology), ADENOSINE triphosphatase, ELECTROPHYSIOLOGY, BILAYER lipid membranes |
| مستخلص: |
Background/Aims: The permeability transition pore (PTP) is an unselective, Ca2+-dependent high conductance channel of the inner mitochondrial membrane whose molecular identity has long remained a mystery. The most recent hypothesis is that pore formation involves the F-ATP synthase, which consistently generates Ca2+-activated channels. Available structures do not display obvious features that can accommodate a channel; thus, how the pore can form and whether its activity can be entirely assigned to F-ATP synthase is the matter of debate. In this study, we investigated the role of F-ATP synthase subunits e, g and b in PTP formation. Methods: Yeast null mutants for e, g and the first transmembrane (TM) a-helix of subunit b were generated and evaluated for mitochondrial morphology (electron microscopy), membrane potential (Rhodamine123 fluorescence) and respiration (Clark electrode). Homoplasmic C23S mutant of subunit a was generated by in vitro mutagenesis followed by biolistic transformation. F-ATP synthase assembly was evaluated by BN-PAGE analysis. Cu2+ treatment was used to induce the formation of F-ATP synthase dimers in the absence of e and g subunits. The electrophysiological properties of F-ATP synthase were assessed in planar lipid bilayers. Results: Null mutants for the subunits e and g display dimer formation upon Cu2+ treatment and show PTP-dependent mitochondrial Ca2+ release but not swelling. Cu2+ treatment causes formation of disulfide bridges between Cys23 of subunits a that stabilize dimers in absence of e and g subunits and favors the open state of wild-type F-ATP synthase channels. Absence of e and g subunits decreases conductance of the F-ATP synthase channel about tenfold. Ablation of the first TM of subunit b, which creates a distinct lateral domain with e and g, further affected channel activity. Conclusion: F-ATP synthase e, g and b subunits create a domain within the membrane that is critical for the generation of the high-conductance channel, thus is a prime candidate for PTP formation. Subunits e and g are only present in eukaryotes and may have evolved to confer this novel function to F-ATP synthase. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
Complementary Index |
