scholarly journals Shedding light on the mitochondrial matrix through a functional membrane transporter

2020 ◽  
Vol 11 (4) ◽  
pp. 1052-1065 ◽  
Author(s):  
Alberto Blázquez-Moraleja ◽  
Ines Sáenz-de-Santa María ◽  
María D. Chiara ◽  
Delia Álvarez-Fernández ◽  
Inmaculada García-Moreno ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane ◽  
Living Cells ◽  
Membrane Transporter ◽  
Mitochondrial Matrix ◽  
Functional Membrane

A BODIPY derivative of carnitine enters mitochondria regardless of their membrane potential and in an enantioselective way through a specific mitochondrial membrane transporter in living cells.

scholarly journals Development of a High Throughput Screening Assay for Mitochondrial Membrane Potential in Living Cells

2002 ◽  
Vol 7 (4) ◽  
pp. 383-389 ◽  
Author(s):  
Shu-Gui Huang
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
High Throughput ◽  
High Throughput Screening ◽  
Mitochondrial Membrane ◽  
Living Cells ◽  
Screening Assay ◽  
Mitochondrial Inner Membrane ◽  
Obesity And Diabetes ◽  
High Throughput Screening Assay

The mitochondrion plays a pivotal role in energy metabolism in eukaryotic cells. The electrochemical potential across the mitochondrial inner membrane is regulated to cope with cellular energy needs and thus reflects the bioenergetic state of the cell. Traditional assays for mitochondrial membrane potential are not amenable to high-throughput drug screening. In this paper, I describe a high-throughput assay that measures the mitochondrial membrane potential of living cells in 96- or 384-well plates. Cells were first treated with test compounds and then with a fluorescent potentiometric probe, the cationic-lipophilic dye tetramethylrhodamine methyl ester (TMRM). The cells were then washed to remove free compounds and probe. The amount of TMRM retained in the mitochondria, which is proportional to the mitochondrial membrane potential, was measured on an LJL Analyst fluorescence reader. Under optimal conditions, the assay measured only the mitochondrial membrane potential. The chemical uncouplers carbonylcyanide m-chlorophenyl hydrazone and dinitrophenol decreased fluorescence intensity, with IC50 values (concentration at 50% inhibition) similar to those reported in the literature. A Z' factor of greater than 0.5 suggests that this cell-based assay can be adapted for high-throughput screening of chemical libraries. This assay may be used in screens for drugs to treat metabolic disorders such as obesity and diabetes, as well as cancer and neurodegenerative diseases.

scholarly journals Effect of local anaesthetics on mitochondrial membrane potential in living cells

1990 ◽  
Vol 271 (1) ◽  
pp. 269-272 ◽  
Author(s):  
M Grouselle ◽  
O Tueux ◽  
P Dabadie ◽  
D Georgescaud ◽  
J P Mazat
Keyword(s):  
Cell Culture ◽  
Membrane Potential ◽  
Local Anaesthetic ◽  
Mitochondrial Membrane ◽  
Transmembrane Potential ◽  
Local Anaesthetics ◽  
Living Cells ◽  
Lipid Solubility ◽  
Laser Dye ◽  
Lipophilic Anion

Using the laser dye rhodamine 123, we demonstrated that local anaesthetics can reach mitochondria in cell culture and reversibly decrease, or even collapse, their transmembrane potential. This effect is highly dependent on the lipid-solubility of the local anaesthetic and can be facilitated by the presence of a lipophilic anion.

scholarly journals A membrane-activatable near-infrared fluorescent probe with ultra-photostability for mitochondrial membrane potentials

The Analyst ◽  
2016 ◽  
Vol 141 (12) ◽  
pp. 3679-3685 ◽  
Author(s):  
Wei Ren ◽  
Ao Ji ◽  
Omran Karmach ◽  
David G. Carter ◽  
Manuela M. Martins-Green ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Fluorescent Probe ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Near Infrared ◽  
Living Cells ◽  
Membrane Potentials ◽  
Fluorescence Quencher

Dark for light: A fluorescence quencher was turned into a near-infrared probe for mitochondrial membrane potential in living cells and mice.

scholarly journals Monitoring of relative mitochondrial membrane potential in living cells by fluorescence microscopy.

1981 ◽  
Vol 88 (3) ◽  
pp. 526-535 ◽  
Author(s):  
L V Johnson ◽  
M L Walsh ◽  
B J Bockus ◽  
L B Chen
Keyword(s):  
Membrane Potential ◽  
Fluorescence Microscopy ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Specific Interaction ◽  
Living Cells ◽  
Cellular Level ◽  
Energy Requirements ◽  
Active Movement ◽  
Biological Functions

Permeant cationic fluorescent probes are shown to be selectively accumulated by the mitochondria of living cells. Mitochondria-specific interaction of such molecules is apparently dependent on the high trans-membrane potential (inside negative) maintained by functional mitochondria. Dissipation of the mitochondrial trans-membrane and potential by ionophores or inhibitors of electron transport eliminates the selective mitochondrial association of these compounds. The application of such potential-dependent probes in conjunction with fluorescence microscopy allows the monitoring of mitochondrial membrane potential in individual living cells. Marked elevations in mitochondria-associated probe fluorescence have been observed in cells engaged in active movement. This approach to the analysis of mitochondrial membrane potential should be of value in future investigations of the control of energy metabolism and energy requirements of specific biological functions at the cellular level.

scholarly journals Calcium-ion transport by intact synaptosomes. Intrasynaptosomal compartmentation and the role of the mitochondrial membrane potential

1980 ◽  
Vol 192 (3) ◽  
pp. 873-880 ◽  
Author(s):  
I D Scott ◽  
K E Akerman ◽  
D G Nicholls
Keyword(s):  
Plasma Membrane ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Calcium Ion ◽  
Mitochondrial Membrane ◽  
Mitochondrial Matrix ◽  
Free Medium ◽  
Rapid Phase ◽  
Calcium Ion Transport

The association of Ca2+ with isolated nerve endings (synaptosomes) is investigated and resolved into two components, that bound to the outer surface of the plasma membrane and that transported across the plasma membrane. When synaptosomes are added directly to a Ca2+-containing medium, there is an initial rapid uptake of Ca2+ across the plasma membrane, followed by a slow uptake that proceeds for 20 min. The rapid phase is not observed if the synaptosomes are initially pre-incubated in a Ca2+-free medium. Rapid disruption of synaptosomes reveals that less than 3 nmol of transported Ca2+ per mg of synaptosomal protein can be ascribed to non-mitochondrial components, whereas the remainder, up to 79% of the total, is further transported into the mitochondrial matrix. Abolition of oxidative phosphorylation while the mitochondrial membrane potential is retained leads to a time-dependent increase in transported Ca2+, whereas abolition of the mitochondrial membrane potential decreases both plasma-membrane transport and accumulation of Ca2+ in the mitochondrial matrix. It is concluded that intrasynaptosomal mitochondria are major regulators of synaptosomal Ca2+.

scholarly journals Two distinct membrane potential–dependent steps drive mitochondrial matrix protein translocation

2016 ◽  
Vol 216 (1) ◽  
pp. 83-92 ◽  
Author(s):  
Alexander Benjamin Schendzielorz ◽  
Christian Schulz ◽  
Oleksandr Lytovchenko ◽  
Anne Clancy ◽  
Bernard Guiard ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane ◽  
Matrix Protein ◽  
Protein Translocation ◽  
Driving Forces ◽  
Matrix Proteins ◽  
Mitochondrial Matrix ◽  
Inner Mitochondrial Membrane ◽  
The Matrix ◽  
Energy Dependent

Two driving forces energize precursor translocation across the inner mitochondrial membrane. Although the membrane potential (Δψ) is considered to drive translocation of positively charged presequences through the TIM23 complex (presequence translocase), the activity of the Hsp70-powered import motor is crucial for the translocation of the mature protein portion into the matrix. In this study, we show that mitochondrial matrix proteins display surprisingly different dependencies on the Δψ. However, a precursor’s hypersensitivity to a reduction of the Δψ is not linked to the respective presequence, but rather to the mature portion of the polypeptide chain. The presequence translocase constituent Pam17 is specifically recruited by the receptor Tim50 to promote the transport of hypersensitive precursors into the matrix. Our analyses show that two distinct Δψ-driven translocation steps energize precursor passage across the inner mitochondrial membrane. The Δψ- and Pam17-dependent import step identified in this study is positioned between the two known energy-dependent steps: Δψ-driven presequence translocation and adenosine triphosphate–driven import motor activity.

scholarly journals Alternative Targets for Modulators of Mitochondrial Potassium Channels

Molecules ◽  
2022 ◽  
Vol 27 (1) ◽  
pp. 299
Author(s):  
Antoni Wrzosek ◽  
Shur Gałecka ◽  
Monika Żochowska ◽  
Anna Olszewska ◽  
Bogusz Kulawiak
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
Membrane Potential ◽  
Potassium Channels ◽  
Mitochondrial Membrane ◽  
Ischemia Reperfusion ◽  
Chemical Compounds ◽  
Oxygen Species ◽  
Mitochondrial Matrix ◽  
Potassium Influx

Mitochondrial potassium channels control potassium influx into the mitochondrial matrix and thus regulate mitochondrial membrane potential, volume, respiration, and synthesis of reactive oxygen species (ROS). It has been found that pharmacological activation of mitochondrial potassium channels during ischemia/reperfusion (I/R) injury activates cytoprotective mechanisms resulting in increased cell survival. In cancer cells, the inhibition of these channels leads to increased cell death. Therefore, mitochondrial potassium channels are intriguing targets for the development of new pharmacological strategies. In most cases, however, the substances that modulate the mitochondrial potassium channels have a few alternative targets in the cell. This may result in unexpected or unwanted effects induced by these compounds. In our review, we briefly present the various classes of mitochondrial potassium (mitoK) channels and describe the chemical compounds that modulate their activity. We also describe examples of the multidirectional activity of the activators and inhibitors of mitochondrial potassium channels.

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