The Use of Cardiolipin-Containing Liposomes as a Model System to Study the Interaction Between Proteins and the Inner Mitochondrial Membrane

2013 ◽  
pp. 147-155 ◽  
Author(s):  
Milit Marom ◽  
Abdussalam Azem
Keyword(s):  
Mitochondrial Membrane ◽  
Model System ◽  
Inner Mitochondrial Membrane

Modulation of the calcium-activated BK-channel of the inner mitochondrial membrane by hypoxia

2007 ◽  
Vol 34 (S 2) ◽  
Author(s):  
D Siemen ◽  
Y Cheng ◽  
X Gu ◽  
P Bednarczyk ◽  
GG Haddad ◽  
...  
Keyword(s):  
Mitochondrial Membrane ◽  
Bk Channel ◽  
Inner Mitochondrial Membrane

The Efects of Spaceflight on Mitochondria in Human Lymphocytes (Jurkat).

1999 ◽  
Vol 5 (S2) ◽  
pp. 1118-1119
Author(s):  
Heide Schatten ◽  
Marian Lewis
Keyword(s):  
Mitochondrial Membrane ◽  
Space Shuttle ◽  
Human Lymphocytes ◽  
Jurkat Cells ◽  
Apoptotic Bodies ◽  
Inner Mitochondrial Membrane ◽  
Mitochondrial Alterations ◽  
Mitochondrial Volume ◽  
Number Of Cells ◽  
Related Increase

Spaceflight induced mitochondrial alterations have been reported for muscle and may be associated with altered physiological functions in space. Mitochondrial alterations are also indicative of preapoptotic events which are seen in greater amounts in cells exposed to spaceflight when compared with cells cultured at 1 g. Preapoptotic mitochondrial changes include alterations of processes at the inner mitochondrial membrane and can result in changes in mitochondrial volume. Higher amounts of oxidative stress during space flight may be one of the causes for changes which lead to apoptosis. Jurkat cells flown on the STS-76 space shuttle mission showed an increase in the number of cells with apoptotic bodies early in the mission and a time-dependent, microgravity-related increase in the Fas/APO-1 cell death factor. Here we investigated the morphology of mitochondria in Jurkat cells exposed to spaceflight during the STS-76 mission.

scholarly journals Paracoccus denitrificans: a genetically tractable model system for studying respiratory complex I

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Owen D. Jarman ◽  
Olivier Biner ◽  
John J. Wright ◽  
Judy Hirst
Keyword(s):  
Complex I ◽  
Paracoccus Denitrificans ◽  
Model System ◽  
Proton Pumping ◽  
Model Systems ◽  
Metabolic Enzyme ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Inner Mitochondrial Membrane

AbstractMitochondrial complex I (NADH:ubiquinone oxidoreductase) is a crucial metabolic enzyme that couples the free energy released from NADH oxidation and ubiquinone reduction to the translocation of four protons across the inner mitochondrial membrane, creating the proton motive force for ATP synthesis. The mechanism by which the energy is captured, and the mechanism and pathways of proton pumping, remain elusive despite recent advances in structural knowledge. Progress has been limited by a lack of model systems able to combine functional and structural analyses with targeted mutagenic interrogation throughout the entire complex. Here, we develop and present the α-proteobacterium Paracoccus denitrificans as a suitable bacterial model system for mitochondrial complex I. First, we develop a robust purification protocol to isolate highly active complex I by introducing a His6-tag on the Nqo5 subunit. Then, we optimize the reconstitution of the enzyme into liposomes, demonstrating its proton pumping activity. Finally, we develop a strain of P. denitrificans that is amenable to complex I mutagenesis and create a catalytically inactive variant of the enzyme. Our model provides new opportunities to disentangle the mechanism of complex I by combining mutagenesis in every subunit with established interrogative biophysical measurements on both the soluble and membrane bound enzymes.

scholarly journals Mitochondrial Fusion in Yeast Requires the Transmembrane GTPase Fzo1p

1998 ◽  
Vol 143 (2) ◽  
pp. 359-373 ◽  
Author(s):  
Greg J. Hermann ◽  
John W. Thatcher ◽  
John P. Mills ◽  
Karen G. Hales ◽  
Margaret T. Fuller ◽  
...  
Keyword(s):  
Mitochondrial Membrane ◽  
Fusion Reaction ◽  
Point Mutations ◽  
Integral Membrane Protein ◽  
Mitochondrial Fusion ◽  
Inner Mitochondrial Membrane ◽  
Fusion Event ◽  
Gtpase Domain ◽  
Developmentally Regulated ◽  
Mitochondrial Reticulum

Membrane fusion is required to establish the morphology and cellular distribution of the mitochondrial compartment. In Drosophila, mutations in the fuzzy onions (fzo) GTPase block a developmentally regulated mitochondrial fusion event during spermatogenesis. Here we report that the yeast orthologue of fuzzy onions, Fzo1p, plays a direct and conserved role in mitochondrial fusion. A conditional fzo1 mutation causes the mitochondrial reticulum to fragment and blocks mitochondrial fusion during yeast mating. Fzo1p is a mitochondrial integral membrane protein with its GTPase domain exposed to the cytoplasm. Point mutations that alter conserved residues in the GTPase domain do not affect Fzo1p localization but disrupt mitochondrial fusion. Suborganellar fractionation suggests that Fzo1p spans the outer and is tightly associated with the inner mitochondrial membrane. This topology may be required to coordinate the behavior of the two mitochondrial membranes during the fusion reaction. We propose that the fuzzy onions family of transmembrane GTPases act as molecular switches to regulate a key step in mitochondrial membrane docking and/or fusion.

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