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Margineantu DH, Emerson CB, Diaz D, Hockenbery DM. Hsp90 inhibition decreases mitochondrial protein turnover. PLoS One 2007; 2:e1066. [PMID: 17957250 PMCID: PMC2031825 DOI: 10.1371/journal.pone.0001066] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Accepted: 09/28/2007] [Indexed: 12/31/2022] Open
Abstract
Background Cells treated with hsp90 inhibitors exhibit pleiotropic changes, including an expansion of the mitochondrial compartment, accompanied by mitochondrial fragmentation and condensed mitochondrial morphology, with ultimate compromise of mitochondrial integrity and apoptosis. Findings We identified several mitochondrial oxidative phosphorylation complex subunits, including several encoded by mtDNA, that are upregulated by hsp90 inhibitors, without corresponding changes in mRNA abundance. Post-transcriptional accumulation of mitochondrial proteins observed with hsp90 inhibitors is also seen in cells treated with proteasome inhibitors. Detailed studies of the OSCP subunit of mitochondrial F1F0-ATPase revealed the presence of mono- and polyubiquitinated OSCP in mitochondrial fractions. We demonstrate that processed OSCP undergoes retrotranslocation to a trypsin-sensitive form associated with the outer mitochondrial membrane. Inhibition of proteasome or hsp90 function results in accumulation of both correctly targeted and retrotranslocated mitochondrial OSCP. Conclusions Cytosolic turnover of mitochondrial proteins demonstrates a novel connection between mitochondrial and cytosolic compartments through the ubiquitin-proteasome system. Analogous to defective protein folding in the endoplasmic reticulum, a mitochondrial unfolded protein response may play a role in the apoptotic effects of hsp90 and proteasome inhibitors.
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Affiliation(s)
- Daciana H. Margineantu
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Christine B. Emerson
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Dolores Diaz
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - David M. Hockenbery
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- * To whom correspondence should be addressed. E-mail:
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Onorato TM, Haldar D. Casein kinase II stimulates rat liver mitochondrial glycerophosphate acyltransferase activity. Biochem Biophys Res Commun 2002; 296:1091-6. [PMID: 12207885 DOI: 10.1016/s0006-291x(02)02064-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Rat liver mitochondrial glycerophosphate acyltransferase (mtGAT) possesses 14 consensus sites for casein kinase II (CKII) phosphorylation. To study the functional relevance of phosphorylation to the activity of mtGAT, we treated isolated rat liver mitochondria with CKII and found that CKII stimulated mtGAT activity approximately 2-fold. Protein phosphatase-lambda treatment reversed the stimulation of mtGAT by CKII. Labeling of both solubilized and non-solubilized mitochondria with CKII and [gamma-32P]ATP resulted in a 32P-labeled protein of 85kDa, the molecular weight of mtGAT. Our findings suggest that CKII stimulates mtGAT activity by phosphorylation of the acyltransferase. The significance of this observation with respect to hormonal control of the enzyme is discussed.
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Affiliation(s)
- Thomas M Onorato
- Department of Biological Sciences, St. John's University, 8000 Utopia Pkwy, 11439, Jamaica, NY, USA
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Marcotte EM, Xenarios I, van Der Bliek AM, Eisenberg D. Localizing proteins in the cell from their phylogenetic profiles. Proc Natl Acad Sci U S A 2000; 97:12115-20. [PMID: 11035803 PMCID: PMC17303 DOI: 10.1073/pnas.220399497] [Citation(s) in RCA: 171] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We introduce a computational method for identifying subcellular locations of proteins from the phylogenetic distribution of the homologs of organellar proteins. This method is based on the observation that proteins localized to a given organelle by experiments tend to share a characteristic phylogenetic distribution of their homologs-a phylogenetic profile. Therefore any other protein can be localized by its phylogenetic profile. Application of this method to mitochondrial proteins reveals that nucleus-encoded proteins previously known to be destined for mitochondria fall into three groups: prokaryote-derived, eukaryote-derived, and organism-specific (i.e., found only in the organism under study). Prokaryote-derived mitochondrial proteins can be identified effectively by their phylogenetic profiles. In the yeast Saccharomyces cerevisiae, 361 nucleus-encoded mitochondrial proteins can be identified at 50% accuracy with 58% coverage. From these values and the proportion of conserved mitochondrial genes, it can be inferred that approximately 630 genes, or 10% of the nuclear genome, is devoted to mitochondrial function. In the worm Caenorhabditis elegans, we estimate that there are approximately 660 nucleus-encoded mitochondrial genes, or 4% of its genome, with approximately 400 of these genes contributed from the prokaryotic mitochondrial ancestor. The large fraction of organism-specific and eukaryote-derived genes suggests that mitochondria perform specialized roles absent from prokaryotic mitochondrial ancestors. We observe measurably distinct phylogenetic profiles among proteins from different subcellular compartments, allowing the general use of prokaryotic genomes in learning features of eukaryotic proteins.
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Affiliation(s)
- E M Marcotte
- Molecular Biology Institute, University of California Los Angeles, 90095, USA
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Abstract
Proteomic research, for its part, is benefiting enormously from the last decade of genomic research as we now have archived, annotated and audited sequence databases to correlate and query experimental data. While the two-dimensional electrophoresis (2-DE) gels are still a central part of proteomics, we reflect on the possibilities and realities of the current 2-DE technology with regard to displaying and analysing proteomes. Limitations of analysing whole cell/tissue lysates by 2-DE alone are discussed, and we investigate whether extremely narrow p/ranges (1 pH unit/25 cm) provide a solution to display comprehensive protein expression profiles. We are confronted with a challenging task: the dynamic range of protein expression. We believe that most of the existing technology is capable of displaying many more proteins than is currently achievable by integrating existing and new techniques to prefractionate samples prior to 2-DE display or analysis. The availability of a "proteomics toolbox", consisting of defined reagents, methods, and equipment, would assist a comprehensive analysis of defined biological systems.
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Affiliation(s)
- G L Corthals
- The Garvan Institute of Medical Research, St Vincent's Hospital, Sydney NSW, Australia.
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Junankar PR, Dulhunty AF, Curtis SM, Pace SM, Thinnes FP. Porin-type 1 proteins in sarcoplasmic reticulum and plasmalemma of striated muscle fibres. J Muscle Res Cell Motil 1995; 16:595-610. [PMID: 8750231 DOI: 10.1007/bf00130241] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The location of porin-type 1 proteins in mammalian striated muscle has been assessed using immunogold electron microscopy with an anti-porin 31HL monoclonal antibody as the primary antibody. Gold particles were found on the mitochondrial outer membrane, the sarcoplasmic reticulum and plasmalemma in longitudinal sections of rat and rabbit skeletal muscle and rabbit and sheep cardiac muscle. The relative densities of gold particles in the mitochondrial outer membrane, sarcoplasmic reticulum and plasmalemma were 7:3:1 in white sternomastoid muscle, for example. Skeletal and cardiac sarcoplasmic reticulum vesicles, which had been fractionated by discontinuous sucrose density centrifugation, were subjected to SDS-polyacrylamide gel electrophoresis and Western blotting. The anti-porin 31HL monoclonal antibody detected a band of relative molecular mass (M(r)) 31,000 in all muscle sarcoplasmic reticulum vesicle fractions and also in liver mitochondria. The intensity of immunostaining of the sarcoplasmic reticulum fractions was 2.5-10% that of mitochondrial outer membranes per microgram of membrane protein blotted. Contamination of the sarcoplasmic reticulum fractions by mitochondrial outer membrane was < 0.75% as determined from the specific activity of monoamine oxidase. Thus, only a small part of the porin detected in sarcoplasmic reticulum vesicles can be attributed to mitochondrial contamination. These results show that porin-type1 immunoreactivity is not restricted to mitochondria but found in the sarcoplasmic reticulum and plasmalemma of both mammalian skeletal and cardiac muscle.
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Affiliation(s)
- P R Junankar
- Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, Australia
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Kyrklund T, Meijer J. Lipid composition of liver peroxisomes isolated from untreated and clofibrate-treated mice and rats. Comp Biochem Physiol B Biochem Mol Biol 1994; 109:665-73. [PMID: 7881828 DOI: 10.1016/0305-0491(94)90129-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Peroxisomes were isolated from liver tissue of control and clofibrate-treated adult male NMRI mice and Sprague-Dawley rats. Phospholipids, cholesterol, triglycerides and free fatty acids were measured in the peroxisomes. The fatty acid profiles of the phosphatidylethanolamine, the phosphatidylcholine, the triglyceride and the free fatty acid fractions were also analyzed. Phosphatidylethanolamine was the dominating phospholipid in peroxisomes from untreated animals. The fatty acid profiles of phosphatidylethanolamine, free fatty acids and triglycerides were similar for untreated mice and rats but differences between the species were observed in the pattern derived from phosphatidylcholine. Phosphatidylcholine was the most abundant phospholipid after clofibrate treatment. Clofibrate treatment caused an increase in the concentrations of phospholipids and unsaturated long-chain fatty acids and a decrease in the concentrations of triglycerides, free fatty acids, cholesterol and shorter saturated fatty acids.
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Affiliation(s)
- T Kyrklund
- Department of Histology, University of Gothenburg, Sweden
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Szabó I, De Pinto V, Zoratti M. The mitochondrial permeability transition pore may comprise VDAC molecules. II. The electrophysiological properties of VDAC are compatible with those of the mitochondrial megachannel. FEBS Lett 1993; 330:206-10. [PMID: 7689984 DOI: 10.1016/0014-5793(93)80274-x] [Citation(s) in RCA: 137] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The electrophysiological properties of isolated mitochondrial porin (VDAC), reconstituted in planar bilayers or proteoliposomes, resemble those of the mitochondrial megachannel believed to be the permeability transition pore. In particular, a correspondence was found with regard to the voltage dependence: VDAC was driven to closed states by potentials of either sign, but the effect was not symmetrical; voltages negative in the compartment to which VDAC was added were more effective. The results are consistent with the hypothesis that the PTP may consist of two cooperating VDAC channels, plus presumably an adenine nucleotide carrier dimer and a third component known to be part of the mitochondrial benzodiazepine receptor.
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Affiliation(s)
- I Szabó
- CNR Unit for the Physiology of Mitochondria, Department of Exp. Biomedical Sciences, Padova, Italy
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Limon I, Coupry I, Lanier S, Parini A. Purification and characterization of mitochondrial imidazoline-guanidinium receptive site from rabbit kidney. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)36660-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Benga G, Poruţiu D, Hodârnău A, Ferdinand W. Ultrastructural aspects and amino acid composition of the purified inner and outer membranes of human liver mitochondria as compared to rat liver mitochondria. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1992; 102:123-8. [PMID: 1526116 DOI: 10.1016/0305-0491(92)90283-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
1. The mitochondria isolated from human or rat liver were fractionated into submitochondrial particles and purified inner and outer membrane. According to different marker enzymes the inner membranes were enriched about 5-6-fold and the outer membranes about 12-14-fold. The electron microscopical appearance of the membranes was that expected on the basis of enzymic characterization. 2. A comparison of the average amino acid composition of the membrane proteins from the two types of mitochondria has been made. In the case of submitochondrial particles there were statistically significant differences between the human and rat hydrolysates for only five amino acids. Analysing the purified mitochondrial membranes there were significant differences between the two species for nine amino acids in the case of outer membranes and for 12 amino acids in the case of inner membranes. 3. With one exception all amino acids that were increased or decreased in the outer membrane exhibited a similar trend in the inner membrane of human compared with rat liver mitochondria. It appears that liver mitochondrial membranes have a species-dependent pattern of amino acid composition of their proteins.
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Affiliation(s)
- G Benga
- Department of Cell and Molecular Biology, University of Medicine and Pharmacy Cluj-Napoca, Romania
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Nałecz MJ, Nałecz KA, Azzi A. Purification and functional characterisation of the pyruvate (monocarboxylate) carrier from baker's yeast mitochondria (Saccharomyces cerevisiae). BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1079:87-95. [PMID: 1888767 DOI: 10.1016/0167-4838(91)90028-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Isolated yeast mitochondria were subjected to solubilization by Triton X-114 and the detergent extract was subsequently chromatrographed on dry hydroxyapatite. Purification of the yeast monocarboxylate (pyruvate) carrier was achieved by affinity chromatography on immobilized 2-cyano-4-hydroxycinnamate, as described previously for bovine heart mitochondria (Bolli, R., Nałecz K.A. and Azzi, A. (1989) J. Biol. Chem. 264 18024-18030). The final preparation contained two polypeptides of apparent molecular mass 26 and 50 kDa. The yeast carrier appeared to be less abundant, but more active, than the analogous protein from higher eukaryotes. The carrier was able to catalyse the pyruvate / pyruvate and pyruvate / acetoacetate exchange reactions, both reactions being sensitive to cyanocinnamate and its derivatives, to phenylpyruvate and to mersalyl and p-chloromercuribenzoate. In the pyruvate / acetoacetate exchange reaction (200 mM internal acetoacetate, enzymatic assay), the Km value for external pyruvate was found to be 0.8 mM and the Vmax 135 mumol/min per mg protein. Among other substrates of the yeast carrier, all transported with similar affinity and identical maximal velocity against acetoacetate, we identified 2-oxoisocaproate, 2-oxoisovalerate and 2-oxo-3-methylvalerate. Lactate was not translocated by this carrier with a measurable rate, neither were di- or tricarboxylates.
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Affiliation(s)
- M J Nałecz
- Institute of Biochemistry and Molecular Biology, University of Berne, Switzerland
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