Related Experiment Video
Updated: Jun 8, 2025
07:35
Assessment of Open Probability of the Mitochondrial Permeability Transition Pore in the Setting of Coenzyme Q Excess
Published on: June 1, 2022
2.2K
Does a transmembrane sodium gradient control membrane potential in mammalian mitochondria?
1Buck Institute for Research on Aging, Novato CA, 94945, USA.
Cell Calcium
|November 2, 2024
Summary
A new study suggests sodium gradients, not just protons, significantly contribute to mitochondrial membrane potential. This challenges established chemiosmotic theories in cellular energy production.
Area of Science:
- Mitochondrial physiology
- Bioenergetics
- Cellular respiration
Background:
- The mitochondrial membrane potential is crucial for ATP synthesis.
- Established models primarily attribute this potential to proton gradients.
- The role of other ion gradients remains less understood.
Purpose of the Study:
- To investigate the contribution of sodium gradients to the mitochondrial membrane potential.
- To challenge the conventional chemiosmotic model of mitochondrial energy transduction.
Main Methods:
- Electrophysiological measurements.
- Chemiosmotic analysis.
- Biochemical assays assessing ion transport.
Main Results:
- A sodium (Na+) gradient across the inner mitochondrial membrane can account for approximately 50% of the mitochondrial membrane potential.
- This gradient is generated by Na+/H+ activity linked to Complex I.
- Findings contradict established electrophysiological and chemiosmotic principles.
Conclusions:
- Sodium gradients play a substantial, previously underestimated role in establishing mitochondrial membrane potential.
- The study necessitates a revision of current models of mitochondrial bioenergetics.
- Complex I's function extends beyond proton translocation to include significant sodium ion transport impacting membrane potential.
Related Concept Videos
01:32Chemiosmosis
97.2K
Oxidative phosphorylation is a highly efficient process that generates large amounts of adenosine triphosphate (ATP), the basic unit of energy that drives many cellular processes. Oxidative phosphorylation involves two processes— the electron transport chain and chemiosmosis.
Electron Transport Chain
The electron transport chain involves a series of protein complexes on the inner mitochondrial membrane that undergo a series of redox reactions. At the end of this chain, the electrons...
Electron Transport Chain
The electron transport chain involves a series of protein complexes on the inner mitochondrial membrane that undergo a series of redox reactions. At the end of this chain, the electrons...
97.2K
01:37Energy to Drive Translocation
2.0K
Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...
Generally, polypeptides are unfolded by two distinct...
2.0K
01:24Resting Membrane Potential
18.0K
The relative difference in electrical charge, or voltage, between the inside and the outside of a cell membrane, is called the membrane potential. It is generated by differences in permeability of the membrane to various ions and the concentrations of these ions across the membrane.
The Inside of a Neuron is More Negative
The membrane potential of a cell can be measured by inserting a microelectrode into a cell and comparing the charge to a reference electrode in the extracellular fluid. The...
The Inside of a Neuron is More Negative
The membrane potential of a cell can be measured by inserting a microelectrode into a cell and comparing the charge to a reference electrode in the extracellular fluid. The...
18.0K
01:21The Resting Membrane Potential
130.7K
Overview
130.7K
01:15Resting Potential Decay
4.8K
The resting membrane potential of a neuron (-70mV) is sustained due to the selective ion permeability of the membrane. At the resting potential, the membrane is slightly permeable to ions like sodium (Na+) and chloride (Cl−) and highly permeable to potassium ions (K+). Differences in the ions' concentration inside the cell compared to the outside are maintained by membrane transport proteins like channels and pumps.
At rest, the K+ is the main ion that moves across the membrane...
At rest, the K+ is the main ion that moves across the membrane...
4.8K
01:28The Inner Mitochondrial Membrane
3.3K
The inner mitochondrial membrane is the primary site of ATP synthesis. The inner membrane domain that forms a smooth layer adjacent to the outer membrane is called the inner boundary membrane. This domain contains membrane transporters that drive metabolites in and out of the mitochondria. In contrast, the inner membrane network that invaginates into the matrix space is called the cristae membrane. This domain accounts for principle mitochondrial function as it accommodates the protein...
3.3K