Distribution of protein disulphide isomerase in rat liver mitochondria

2001 ◽  
Vol 356 (2) ◽  
pp. 567-570 ◽  
Author(s):  
Maria Pia RIGOBELLO ◽  
Arianna DONELLA-DEANA ◽  
Luca CESARO ◽  
Alberto BINDOLI
Keyword(s):  
Thioredoxin Reductase ◽  
Immunoblot Analysis ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Specific Marker ◽  
Protein Disulphide Isomerase ◽  
Mitochondrial Functions ◽  
The Matrix ◽  
Molecular Masses

Here we report the localization of protein disulphide isomerase (PDI) in the mitochondrial compartments, comparing it with that of thioredoxin reductase. The latter enzyme is present mostly in the matrix, whereas PDI is located at the level of the outer membrane. We characterize the different submitochondrial fractions with specific marker enzymes. PDI, whether isolated from whole mitochondria or from purified outer membranes, exhibits the same electrophoretic mobility, indicating identical molecular masses. Moreover, immunoblot analysis with monoclonal anti-PDI antibody shows immunoreactivity only with the microsomal PDI, indicating the specificity of the mitochondrial isoform. The significance of these findings is discussed with reference to the potential role of PDI and thioredoxin reductase in regulating the mitochondrial functions dependent on the thiol–disulphide transition.

Ceramide induces cytochrome c release from isolated mitochondria

1999 ◽  
Vol 66 ◽  
pp. 27-31 ◽  
Author(s):  
Christoph Richter ◽  
Pedram Ghafourifar
Keyword(s):  
Cytochrome C ◽  
Membrane Integrity ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Cytochrome C Release ◽  
Mitochondrial Oxygen Consumption ◽  
Mitochondrial Functions ◽  
Cyt C ◽  
C6 Ceramide

This chapter addresses the role of mitochondria in apoptosis. Emphasis is put on the recently observed influence of ceramides on mitochondrial functions. We report here that N-acetylsphingosine (C2-ceramide), N-hexanoylsphingosine (C6-ceramide) and, to a much lesser extent, C2-dihydroceramide, induce cytochrome c (cyt c) release from isolated rat liver mitochondria. Ceramide-induced cyt c release is prevented by a low concentration of Bcl-2. The release takes place when cyt c is oxidized, but not when it is reduced. Upon cyt c release mitochondrial oxygen consumption, mitochondrial transmembrane potential (ΔΨm) and Ca2+ retention are diminished. Bcl-2 prevents, and addition of cyt c reverses, the alteration of these mitochondrial functions. In ATP-energized mitochondria ceramides do not alter ΔΨm, neither when cyt c is oxidized nor when it is reduced. This rules out a non-specific disturbance by ceramides of mitochondrial-membrane integrity. It is concluded that some of the apoptogenic properties of ceramides are mediated via their interaction with mitochondrial cyt c followed by its release.

scholarly journals Mmf1p, a Novel Yeast Mitochondrial Protein Conserved throughout Evolution and Involved in Maintenance of the Mitochondrial Genome

2000 ◽  
Vol 20 (20) ◽  
pp. 7784-7797 ◽  
Author(s):  
Ellinor Oxelmark ◽  
Antonio Marchini ◽  
Ilaria Malanchi ◽  
Francesca Magherini ◽  
Laurence Jaquet ◽  
...  
Keyword(s):  
Mitochondrial Protein ◽  
Liver Mitochondria ◽  
Leader Peptide ◽  
Rat Liver Mitochondria ◽  
Biological Functions ◽  
Direct Role ◽  
The Matrix ◽  
Nonfermentable Carbon Source ◽  
Novel Protein

ABSTRACT A novel protein family (p14.5, or YERO57c/YJGFc) highly conserved throughout evolution has recently been identified. The biological role of these proteins is not yet well characterized. Two members of the p14.5 family are present in the yeast Saccharomyces cerevisiae. In this study, we have characterized some of the biological functions of the two yeast proteins. Mmf1p is a mitochondrial matrix factor, and homologous Mmf1p factor (Hmf1p) copurifies with the soluble cytoplasmic fraction. Δmmf1cells lose mitochondrial DNA (mtDNA) and have a decreased growth rate, while Δhmf1 cells do not display any visible phenotype. Furthermore, we demonstrate by genetic analysis that Mmf1p does not play a direct role in replication and segregation of the mtDNA. rho+ Δmmf1 haploid cells can be obtained when tetrads are directly dissected on medium containing a nonfermentable carbon source. Our data also indicate that Mmf1p and Hmf1p have similar biological functions in different subcellular compartments. Hmf1p, when fused with the Mmf1p leader peptide, is transported into mitochondria and is able to functionally replace Mmf1p. Moreover, we show that homologous mammalian proteins are functionally related to Mmf1p. Human p14.5 localizes in yeast mitochondria and rescues the Δmmf1-associated phenotypes. In addition, fractionation of rat liver mitochondria showed that rat p14.5, like Mmf1p, is a soluble protein of the matrix. Our study identifies a biological function for Mmf1p and furthermore indicates that this function is conserved between members of the p14.5 family.

scholarly journals Identification of the human mitochondrial S-adenosylmethionine transporter: bacterial expression, reconstitution, functional characterization and tissue distribution

2004 ◽  
Vol 379 (1) ◽  
pp. 183-190 ◽  
Author(s):  
G. AGRIMI ◽  
M. A. Di NOIA ◽  
C. M. T. MAROBBIO ◽  
G. FIERMONTE ◽  
F. M. LASORSA ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Physiological Role ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Bromocresol Purple ◽  
Human Cdna Sequence ◽  
Its Gene ◽  
The Matrix

The mitochondrial carriers are a family of transport proteins that, with a few exceptions, are found in the inner membranes of mitochondria. They shuttle metabolites and cofactors through this membrane, and connect cytoplasmic functions with others in the matrix. SAM (S-adenosylmethionine) has to be transported into the mitochondria where it is converted into S-adenosylhomocysteine in methylation reactions of DNA, RNA and proteins. The transport of SAM has been investigated in rat liver mitochondria, but no protein has ever been associated with this activity. By using information derived from the phylogenetically distant yeast mitochondrial carrier for SAM and from related human expressed sequence tags, a human cDNA sequence was completed. This sequence was overexpressed in bacteria, and its product was purified, reconstituted into phospholipid vesicles and identified from its transport properties as the human mitochondrial SAM carrier (SAMC). Unlike the yeast orthologue, SAMC catalysed virtually only countertransport, exhibited a higher transport affinity for SAM and was strongly inhibited by tannic acid and Bromocresol Purple. SAMC was found to be expressed in all human tissues examined and was localized to the mitochondria. The physiological role of SAMC is probably to exchange cytosolic SAM for mitochondrial S-adenosylhomocysteine. This is the first report describing the identification and characterization of the human SAMC and its gene.

scholarly journals Distribution of protein disulphide isomerase in rat liver mitochondria

2001 ◽  
Vol 356 (2) ◽  
pp. 567 ◽  
Author(s):  
Maria Pia RIGOBELLO ◽  
Arianna DONELLA-DEANA ◽  
Luca CESARO ◽  
Alberto BINDOLI
Keyword(s):  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Protein Disulphide Isomerase

scholarly journals Rat liver mitochondrial ADP-ribose pyrophosphatase in the matrix space with low Km for free ADP-ribose

1994 ◽  
Vol 299 (3) ◽  
pp. 679-682 ◽  
Author(s):  
D Bernet ◽  
R M Pinto ◽  
M J Costas ◽  
J Canales ◽  
J C Cameselle
Keyword(s):  
Rat Liver ◽  
Gradient Centrifugation ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Matrix Space ◽  
The Matrix ◽  
Submitochondrial Fractions

A study involving markers of subcellular and submitochondrial fractions, gradient centrifugation, latency measurements and extraction with digitonin, demonstrates the association of a specific ADP-ribose pyrophosphatase with rat liver mitochondria and its localization in the matrix space. The enzyme hydrolyses ADP-ribose to AMP, with a Km of 2-3 microM. The results support the occurrence of a specific turnover pathway for free ADP-ribose and its relevance in mitochondria.

scholarly journals MORPHOLOGY AND ATP-ASE OF ISOLATED MITOCHONDRIA

1955 ◽  
Vol 1 (2) ◽  
pp. 127-138 ◽  
Author(s):  
Robert F. Witter ◽  
Michael L. Watson ◽  
Mary A. Cottone
Keyword(s):  
Electron Microscope ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Substantial Part ◽  
Mitochondrial Matrix ◽  
Isolated Mitochondria ◽  
The Matrix ◽  
First Time ◽  
Methods Of Isolation

Changes in the morphology of rat liver mitochondria brought about by different methods of isolation and the concomitant changes in ATP-ase activity were studied. The morphology was investigated with the electron microscope. It was found that the ATP-ase activity of the isolated mitochondria cannot be readily correlated with the morphology of the mitochondria. The ATP-ase found in these preparations was latent, resembling the enzyme described in mitochondria prepared in 0.25 M sucrose. In confirmation of earlier results the use of 0.88 M sucrose yielded preparations with a higher initial ATP-ase than did other methods. Preparation in 0.25 M sucrose resulted in round, swollen mitochondria of which 30 to 40 per cent appeared to have lost a substantial part of the mitochondrial matrix. Preparations in 0.44 to 0.88 M sucrose contained mainly rod-shaped mitochondria plus a small amount of another type of swollen mitochondria. The matrix of mitochondria isolated in 0.88 M sucrose was highly condensed. By the use of 0.44 M sucrose adjusted to pH 6.2 with citric acid, it was possible to isolate, for the first time, mitochondria closely resembling those in situ and containing latent ATP-ase.

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