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Juhaszova M, Kobrinsky E, Zorov DB, Nuss HB, Yaniv Y, Fishbein KW, de Cabo R, Montoliu L, Gabelli SB, Aon MA, Cortassa S, Sollott SJ. ATP Synthase K +- and H +-Fluxes Drive ATP Synthesis and Enable Mitochondrial K +-"Uniporter" Function: I. Characterization of Ion Fluxes. Function (Oxf) 2021; 3:zqab065. [PMID: 35229078 PMCID: PMC8867323 DOI: 10.1093/function/zqab065] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/06/2021] [Accepted: 12/07/2021] [Indexed: 01/07/2023]
Abstract
ATP synthase (F1Fo) synthesizes daily our body's weight in ATP, whose production-rate can be transiently increased several-fold to meet changes in energy utilization. Using purified mammalian F1Fo-reconstituted proteoliposomes and isolated mitochondria, we show F1Fo can utilize both ΔΨm-driven H+- and K+-transport to synthesize ATP under physiological pH = 7.2 and K+ = 140 mEq/L conditions. Purely K+-driven ATP synthesis from single F1Fo molecules measured by bioluminescence photon detection could be directly demonstrated along with simultaneous measurements of unitary K+ currents by voltage clamp, both blocked by specific Fo inhibitors. In the presence of K+, compared to osmotically-matched conditions in which this cation is absent, isolated mitochondria display 3.5-fold higher rates of ATP synthesis, at the expense of 2.6-fold higher rates of oxygen consumption, these fluxes being driven by a 2.7:1 K+: H+ stoichiometry. The excellent agreement between the functional data obtained from purified F1Fo single molecule experiments and ATP synthase studied in the intact mitochondrion under unaltered OxPhos coupling by K+ presence, is entirely consistent with K+ transport through the ATP synthase driving the observed increase in ATP synthesis. Thus, both K+ (harnessing ΔΨm) and H+ (harnessing its chemical potential energy, ΔμH) drive ATP generation during normal physiology.
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Affiliation(s)
| | | | | | | | | | - Kenneth W Fishbein
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Lluis Montoliu
- National Centre for Biotechnology (CNB-CSIC), Biomedical Research Networking Center on Rare Diseases (CIBERER-ISCIII), 28049, Madrid, Spain
| | - Sandra B Gabelli
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA,Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA,Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Miguel A Aon
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA,Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Sonia Cortassa
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA
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