The control of mitochondrial respiration in yeast: A possible role of the outer mitochondrial membrane

1996 ◽  
Vol 14 (3) ◽  
pp. 201-208 ◽  
Author(s):  
Mojgan Ahmadzadeh ◽  
Andrew Horng ◽  
Marco Colombini
Keyword(s):  
Mitochondrial Respiration ◽  
Mitochondrial Membrane ◽  
Outer Mitochondrial Membrane

scholarly journals Role of Oxidative Phosphorylation in Bax Toxicity

2000 ◽  
Vol 20 (10) ◽  
pp. 3590-3596 ◽  
Author(s):  
Marian H. Harris ◽  
Matthew G. Vander Heiden ◽  
Stephen J. Kron ◽  
Craig B. Thompson
Keyword(s):  
Oxidative Phosphorylation ◽  
Growth Inhibition ◽  
Mitochondrial Respiration ◽  
Mammalian Cells ◽  
Mitochondrial Membrane ◽  
Adenine Nucleotide ◽  
Atp Synthesis ◽  
Outer Mitochondrial Membrane ◽  
Nucleotide Exchange

ABSTRACT The Bcl-2-related protein Bax is toxic when expressed either in yeast or in mammalian cells. Although the mechanism of this toxicity is unknown, it appears to be similar in both cell types and dependent on the localization of Bax to the outer mitochondrial membrane. To investigate the role of mitochondrial respiration in Bax-mediated toxicity, a series of yeast mutant strains was created, each carrying a disruption in either a component of the mitochondrial electron transport chain, a component of the mitochondrial ATP synthesis machinery, or a protein involved in mitochondrial adenine nucleotide exchange. Bax toxicity was reduced in strains lacking the ability to perform oxidative phosphorylation. In contrast, a respiratory-competent strain that lacked the outer mitochondrial membrane Por1 protein showed increased sensitivity to Bax expression. Deficiencies in other mitochondrial proteins did not affect Bax toxicity as long as the ability to perform oxidative phosphorylation was maintained. Characterization of Bax-induced toxicity in wild-type yeast demonstrated a growth inhibition that preceded cell death. This growth inhibition was associated with a decreased ability to carry out oxidative phosphorylation following Bax induction. Furthermore, cells recovered following Bax-induced growth arrest were enriched for a petite phenotype and were no longer able to grow on a nonfermentable carbon source. These results suggest that Bax expression leads to an impairment of mitochondrial respiration, inducing toxicity in cells dependent on oxidative phosphorylation for survival. Furthermore, Bax toxicity is enhanced in yeast deficient in the ability to exchange metabolites across the outer mitochondrial membrane.

scholarly journals How does the TOM complex mediate insertion of precursor proteins into the mitochondrial outer membrane?

2005 ◽  
Vol 171 (3) ◽  
pp. 419-423 ◽  
Author(s):  
Doron Rapaport
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Mitochondrial Membrane ◽  
Mitochondrial Outer Membrane ◽  
Outer Face ◽  
Outer Mitochondrial Membrane ◽  
Lipid Core ◽  
Tom Complex ◽  
Precursor Proteins

A multisubunit translocase of the outer mitochondrial membrane (TOM complex) mediates both the import of mitochondrial precursor proteins into the internal compartments of the organelle and the insertion of proteins residing in the mitochondrial outer membrane. The proposed β-barrel structure of Tom40, the pore-forming component of the translocase, raises the question of how the apparent uninterrupted β-barrel topology can be compatible with a role of Tom40 in releasing membrane proteins into the lipid core of the bilayer. In this review, I discuss insertion mechanisms of proteins into the outer membrane and present alternative models based on the opening of a multisubunit β-barrel TOM structure or on the interaction of outer membrane precursors with the outer face of the Tom40 β-barrel structure.

scholarly journals Mitochondria-Associated Membranes (MAMs) are involved in Bax mitochondrial localization and cytochrome c release

2018 ◽  
Author(s):  
Alexandre Légiot ◽  
Claire Céré ◽  
Thibaud Dupoiron ◽  
Mohamed Kaabouni ◽  
Stéphen Manon
Keyword(s):  
Endoplasmic Reticulum ◽  
Cytochrome C ◽  
Mitochondrial Membrane ◽  
Human Protein ◽  
Outer Mitochondrial Membrane ◽  
Yeast Mutant ◽  
Mitochondrial Localization ◽  
Cytochrome C Release ◽  
Apoptotic Protein

AbstractThe distribution of the pro-apoptotic protein Bax in the outer mitochondrial membrane (OMM) is a central point of regulation of apoptosis. It is now widely recognized that parts of the endoplasmic reticulum (ER) are closely associated to the OMM, and are actively involved in different signalling processes. We adressed a possible role of these domains, called Mitochondria-Associated Membranes (MAMs) in Bax localization and fonction, by expressing the human protein in a yeast mutant deleted of MDM34, a ERMES component (ER-Mitochondria Encounter Structure). By affecting MAMs stability, the deletion of MDM34 altered Bax mitochondrial localization, and decreased its capacity to release cytochrome c. Furthermore, the deletion of MDM34 decreased the size of an uncompletely released, MAMs-associated pool of cytochrome c.

scholarly journals Enzymic hydrolysis of acetylcarnitine in liver from rats, sheep and cows

1975 ◽  
Vol 152 (2) ◽  
pp. 161-166 ◽  
Author(s):  
N. D. Costa ◽  
A. M. Snoswell
Keyword(s):  
Membrane Fraction ◽  
Mitochondrial Membrane ◽  
Physiological Role ◽  
Outer Mitochondrial Membrane ◽  
Carnitine Acetyltransferase ◽  
Enzymic Hydrolysis ◽  
Liver Homogenates ◽  
Hydrolysis Of ◽  
Hydrolysis Activity

1. The enzymic utilization of O-acetyl-l-carnitine other than via carnitine acetyltransferase (EC 2.3.1.7) was investigated in liver homogenates from rats, sheep and dry cows. 2. An enzymic utilization of O-acetyl-l-carnitine via hydrolysis of the ester bond to yield stoicheiometric quantities of acetate and l-carnitine was demonstrated; 0.55, 0.53 and 0.30μmol of acetyl-l-carnitine were utilized/min per g fresh wt. of liver homogenates from rats, sheep and dry cows respectively. 3. The acetylcarnitine hydrolysis activity was not due to a non-specific esterase or non-specific cholinesterase. O-Acetyl-d-carnitine was not utilized. 4. The activity was associated with the enriched outer mitochondrial membrane fraction from rat liver. Isolation of this fraction resulted in an eightfold purification of acetylcarnitine hydrolase activity. 4. The Km for this acetylcarnitine utilization was 2mm and 1.5mm for rat and sheep liver homogenates respectively. 6. There was a significant increase in acetylcarnitine hydrolase in rats on starvation and cows on lactation and a significant decrease in sheep that were severely alloxan-diabetic. 7. The physiological role of an acetylcarnitine hydrolase is discussed in relation to coupling with carnitine acetyltransferase for the relief of ‘acetyl pressure’.

scholarly journals The role of Fis1p–Mdv1p interactions in mitochondrial fission complex assembly

2005 ◽  
Vol 171 (2) ◽  
pp. 291-301 ◽  
Author(s):  
Mary Anne Karren ◽  
Emily M. Coonrod ◽  
Teresa K. Anderson ◽  
Janet M. Shaw
Keyword(s):  
Mitochondrial Membrane ◽  
Mitochondrial Fission ◽  
Coiled Coil ◽  
Cytoplasmic Domain ◽  
Tetratricopeptide Repeat ◽  
Outer Mitochondrial Membrane ◽  
Complex Assembly ◽  
Binding Surface ◽  
New Evidence

Mitochondrial division requires coordinated interactions among Fis1p, Mdv1p, and the Dnm1p GTPase, which assemble into fission complexes on the outer mitochondrial membrane. The integral outer membrane protein Fis1p contains a cytoplasmic domain consisting of a tetratricopeptide repeat (TPR)–like fold and a short NH2-terminal helix. Although it is known that the cytoplasmic domain is necessary for assembly of Mdv1p and Dnm1p into fission complexes, the molecular details of this assembly are not clear. In this study, we provide new evidence that the Fis1p–Mdv1p interaction is direct. Furthermore, we show that conditional mutations in the Fis1p TPR-like domain cause fission complex assembly defects that are suppressed by mutations in the Mdv1p-predicted coiled coil. We also define separable functions for the Fis1p NH2-terminal arm and TPR-like fold. These studies suggest that the concave binding surface of the Fis1p TPR-like fold interacts with Mdv1p during mitochondrial fission and that Mdv1p facilitates Dnm1p recruitment into functional fission complexes.

Protein translocase of the outer mitochondrial membrane: role of import receptors in the structural organization of the TOM complex

2002 ◽  
Vol 316 (3) ◽  
pp. 657-666 ◽  
Author(s):  
Kirstin Model ◽  
Thorsten Prinz ◽  
Teresa Ruiz ◽  
Michael Radermacher ◽  
Thomas Krimmer ◽  
...  
Keyword(s):  
Mitochondrial Membrane ◽  
Structural Organization ◽  
Outer Mitochondrial Membrane ◽  
Tom Complex ◽  
Import Receptors

The role of contact sites between inner and outer mitochondrial membrane in energy transfer

1990 ◽  
Vol 1018 (2-3) ◽  
pp. 229-233 ◽  
Author(s):  
Klaas Nicolay ◽  
Manuel Rojo ◽  
Theo Wallimann ◽  
Rudy Demel ◽  
Ruud Hovius
Keyword(s):  
Energy Transfer ◽  
Mitochondrial Membrane ◽  
Outer Mitochondrial Membrane ◽  
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