Thyroid Hormone-Induced Changes in Cytoplasmic and Mitochondrial Proteins of a Teleost

1998 ◽  
Vol 53 (1-2) ◽  
pp. 120-124 ◽  
Author(s):  
G. Tripathi
Keyword(s):  
Skeletal Muscle ◽  
Actinomycin D ◽  
De Novo ◽  
Mitochondrial Protein ◽  
Mitochondrial Proteins ◽  
Cytoplasmic Protein ◽  
Freshwater Teleost ◽  
Mitochondrial Fractions ◽  
Induced Changes ◽  
Induced Proteins

AbstractThe effect of triiodothyronine (T3) on the cytoplasmic and mitochondrial protein contents were studied in the liver and skeletal muscle of a freshwater teleost. The fish exposed to thiouracil for 28 days showed 1.5-2 times reduction in the total protein contents of cytoplasmic and mitochondrial fractions. A single injection of T3 to thiouracil exposed fish caused the earliest induction in the liver and skeletal muscle mitochondrial protein and the skeletal muscle cytoplasmic protein at 12 hr of lapses. However, the initial induction in the cytoplasmic protein of the liver was observed at 3 hr after T3 treatment. The maximum inductions (1.5-3.2 fold) in the cytoplasmic and mitochondrial proteins of the liver and skeletal muscle were obtained at 1 8 -2 4 hr following hormonal administration. Thereafter, the cytoplasmic and mitochondrial protein contents of both the tissues declined to their control levels within 3 6 - 4 8 hr of T3 injection which reflected the half-life and turnover period of the induced proteins. These T3 dependent inductions in the cytoplasmic and mitochondrial proteins of the liver (1 .4 -3 .2 fold) and skeletal muscle (1.8 -2.7 fold) were inhibited by actinomycin D and cycloheximide indicating T3-induced de novo synthesis of the proteins. The induction in the cytoplasmic protein (3 fold) was almost double to that of the mitochondrial protein (1.6 fold) suggesting more synthesis of protein molecules in the cytoplasm for cellular and subcellular activities.

Properties of skeletal muscle mitochondria isolated from subsarcolemmal and intermyofibrillar regions

1993 ◽  
Vol 264 (2) ◽  
pp. C383-C389 ◽  
Author(s):  
A. M. Cogswell ◽  
R. J. Stevens ◽  
D. A. Hood
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Mitochondrial Protein ◽  
Mitochondrial Fraction ◽  
Biochemical Properties ◽  
Leucine Incorporation ◽  
Mitochondrial Protein Synthesis ◽  
Skeletal Muscle Mitochondria ◽  
Mitochondrial Fractions

Two mitochondrial fractions, termed intermyofibrillar (IMF) and subsarcolemmal (SS), were isolated from skeletal muscle, and their biochemical properties were related to differences in respiration and mitochondrial protein synthesis. State III respiration was 2.3- to 2.8-fold greater in IMF than in SS mitochondria. Site 1 inhibition of respiration with rotenone reduced this difference to 1.4-fold. When sites 1 and 2 were inhibited with antimycin, the 1.4-fold differences remained. The activities of cytochrome-c oxidase (CYTOX) and succinate dehydrogenase (SDH) could account for some of these differences, since CYTOX was 20% greater (P < 0.05) in IMF mitochondria, and SDH was 40% greater (P < 0.05) in SS mitochondria. Cytochromes a, b, c, and c1 contents were similar in the two fractions. Cardiolipin (CL) content was higher (P < 0.05) in SS mitochondria, indicating a less dense mitochondrial fraction with respect to CL. In vitro [3H]leucine incorporation was 1.8-fold higher (P < 0.05) in IMF than in SS mitochondria. Thus compositional differences between IMF and SS fractions exist, perhaps representing mitochondria at different stages of biogenesis. The biochemical and functional differences could not solely be due to differences in mitochondrial protein synthesis but could also be due to nuclear-directed protein synthesis specific to each mitochondrial fraction.

scholarly journals C6orf203 controls OXPHOS function through modulation of mitochondrial protein biosynthesis

2019 ◽  
Author(s):  
Sara Palacios-Zambrano ◽  
Luis Vázquez-Fonseca ◽  
Cristina González-Páramos ◽  
Laura Mamblona ◽  
Laura Sánchez-Caballero ◽  
...  
Keyword(s):  
De Novo ◽  
Protein Biosynthesis ◽  
Mitochondrial Protein ◽  
Mitochondrial Respiratory Chain ◽  
Culture Conditions ◽  
Mitochondrial Proteins ◽  
Respiratory Chain Complexes ◽  
Central Function ◽  
Mitochondrial Dna Depletion

ABSTRACTMitochondria are essential organelles present in the vast majority of eukaryotic cells. Their central function is to produce cellular energy through the OXPHOS system, and functional alterations provoke so-called mitochondrial OXPHOS diseases. It is estimated that several hundred mitochondrial proteins have unknown functions. Very recently, C6orf203 was described to participate in mitochondrial transcription under induced mitochondrial DNA depletion stress conditions. Here, we describe another role for C6orf203, specifically in OXPHOS biogenesis under regular culture conditions. HEK293T C6orf203-Knockout (KO) cells generated by CRISPR/Cas9 genome editing showed both reduced grow in galactose, as a carbon source, and in their oxygen consumption capability, strongly suggesting an OXPHOS dysfunction. C6orf203-KO also provoked a depletion of OXPHOS proteins and decreased the activity of the mitochondrial respiratory chain complexes. C6orf203 was present in high molecular weight complexes compatible with mitoribosomes, and in vivo labelling of de novo mitochondrial proteins synthesis revealed that C6orf203-KO severely but not completely affected the translation of mitochondrial mRNAs. Taken together, we describe herein a new function for C6orf203, making it a potential OXPHOS disease-related candidate.

scholarly journals Quality control of mitochondrial protein synthesis is required for membrane integrity and cell fitness

2015 ◽  
Vol 211 (2) ◽  
pp. 373-389 ◽  
Author(s):  
Uwe Richter ◽  
Taina Lahtinen ◽  
Paula Marttinen ◽  
Fumi Suomi ◽  
Brendan J. Battersby
Keyword(s):  
Quality Control ◽  
Protein Synthesis ◽  
Oxidative Phosphorylation ◽  
De Novo ◽  
Mitochondrial Protein ◽  
Membrane Integrity ◽  
Mitochondrial Proteins ◽  
Protein Accumulation ◽  
Mitochondrial Protein Synthesis ◽  
Inner Membrane

Mitochondrial ribosomes synthesize a subset of hydrophobic proteins required for assembly of the oxidative phosphorylation complexes. This process requires temporal and spatial coordination and regulation, so quality control of mitochondrial protein synthesis is paramount to maintain proteostasis. We show how impaired turnover of de novo mitochondrial proteins leads to aberrant protein accumulation in the mitochondrial inner membrane. This creates a stress in the inner membrane that progressively dissipates the mitochondrial membrane potential, which in turn stalls mitochondrial protein synthesis and fragments the mitochondrial network. The mitochondrial m-AAA protease subunit AFG3L2 is critical to this surveillance mechanism that we propose acts as a sensor to couple the synthesis of mitochondrial proteins with organelle fitness, thus ensuring coordinated assembly of the oxidative phosphorylation complexes from two sets of ribosomes.

scholarly journals Biallelic Mutations in MTPAP Associated with a Lethal Encephalopathy

2019 ◽  
Vol 51 (03) ◽  
pp. 178-184 ◽  
Author(s):  
Lien Van Eyck ◽  
Francesco Bruni ◽  
Anne Ronan ◽  
Tracy A. Briggs ◽  
Tony Roscioli ◽  
...  
Keyword(s):  
De Novo ◽  
Mitochondrial Gene ◽  
Mitochondrial Protein ◽  
Missense Variant ◽  
Mitochondrial Proteins ◽  
Compound Heterozygous ◽  
Altered Expression ◽  
Mitochondrial Transcripts ◽  
Biallelic Mutations ◽  
First Year Of Life

Abstract Background A homozygous founder mutation in MTPAP/TENT6, encoding mitochondrial poly(A) polymerase (MTPAP), was first reported in six individuals of Old Order Amish descent demonstrating an early-onset, progressive spastic ataxia with optic atrophy and learning difficulties. MTPAP contributes to the regulation of mitochondrial gene expression through the polyadenylation of mitochondrially encoded mRNAs. Mitochondrial mRNAs with severely truncated poly(A) tails were observed in affected individuals, and mitochondrial protein expression was altered. Objective To determine the genetic basis of a perinatal encephalopathy associated with stereotyped neuroimaging and infantile death in three patients from two unrelated families. Methods Whole-exome sequencing was performed in two unrelated patients and the unaffected parents of one of these individuals. Variants and familial segregation were confirmed by Sanger sequencing. Polyadenylation of mitochondrial transcripts and de novo synthesis of mitochondrial proteins were assessed in patient's fibroblasts. Results Compound heterozygous p.Ile428Thr and p.Arg523Trp substitutions in MTPAP were recorded in two affected siblings from one family, and a homozygous p.Ile385Phe missense variant identified in a further affected child from a second sibship. Mitochondrial poly(A) tail analysis demonstrated shorter posttranscriptional additions to the mitochondrial transcripts, as well as an altered expression of mitochondrial proteins in the fibroblasts of the two siblings compared with healthy controls. Conclusion Mutations in MTPAP likely cause an autosomal recessive perinatal encephalopathy with lethality in the first year of life.

scholarly journals In vivo measurement of synthesis rate of individual skeletal muscle mitochondrial proteins

2008 ◽  
Vol 295 (5) ◽  
pp. E1255-E1268 ◽  
Author(s):  
Abdul Jaleel ◽  
Kevin R. Short ◽  
Yan W. Asmann ◽  
Katherine A. Klaus ◽  
Dawn M. Morse ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mitochondrial Dysfunction ◽  
Translational Regulation ◽  
Protein Identification ◽  
Mitochondrial Protein ◽  
Mitochondrial Fraction ◽  
Mitochondrial Proteins ◽  
Synthesis Rate ◽  
Gene Transcripts

Skeletal muscle mitochondrial dysfunction occurs in many conditions including aging and insulin resistance, but the molecular pathways of the mitochondrial dysfunction remain unclear. Presently, no methodologies are available to measure synthesis rates of individual mitochondrial proteins, which limits our ability to fully understand the translational regulation of gene transcripts. Here, we report a methodology to measure synthesis rates of multiple muscle mitochondrial proteins, which, along with large-scale measurements of mitochondrial gene transcripts and protein concentrations, will enable us to determine whether mitochondrial alteration is due to transcriptional or translational changes. The methodology involves in vivo labeling of muscle proteins with l-[ ring-13C6]phenylalanine, protein purification by two-dimensional gel electrophoresis of muscle mitochondrial fraction, and protein identification and stable isotope abundance measurements by tandem mass spectrometry. Synthesis rates of 68 mitochondrial and 23 nonmitochondrial proteins from skeletal muscle mitochondrial fraction showed a 10-fold range, with the lowest rate for a structural protein such as myosin heavy chain (0.16 ± 0.04%/h) and the highest for a mitochondrial protein such as dihydrolipoamide branched chain transacylase E2 (1.5 ± 0.42%/h). This method offers an opportunity to better define the translational regulation of proteins in skeletal muscle or other tissues.

scholarly journals Mitochondrien unter Stress: Die Rolle der Präsequenzprotease MPP

BIOspektrum ◽  
2021 ◽  
Vol 27 (4) ◽  
pp. 390-393
Author(s):  
F.-Nora Vögtle
Keyword(s):  
Stress Response ◽  
Cellular Stress ◽  
Critical Role ◽  
Mitochondrial Protein ◽  
Nuclear Genome ◽  
Cellular Stress Response ◽  
Mitochondrial Proteins ◽  
Protein Biogenesis ◽  
Cellular Integrity

AbstractThe majority of mitochondrial proteins are encoded in the nuclear genome, so that the nearly entire proteome is assembled by post-translational preprotein import from the cytosol. Proteomic imbalances are sensed and induce cellular stress response pathways to restore proteostasis. Here, the mitochondrial presequence protease MPP serves as example to illustrate the critical role of mitochondrial protein biogenesis and proteostasis on cellular integrity.

scholarly journals Skeletal muscle proteomes reveal downregulation of mitochondrial proteins in transition from prediabetes into type 2 diabetes

iScience ◽  
2021 ◽  
pp. 102712
Author(s):  
Tiina Öhman ◽  
Jaakko Teppo ◽  
Neeta Datta ◽  
Selina Mäkinen ◽  
Markku Varjosalo ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Mitochondrial Proteins

scholarly journals Mitochondrial microRNAs: A Putative Role in Tissue Regeneration

Biology ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 486
Author(s):  
Sílvia C. Rodrigues ◽  
Renato M. S. Cardoso ◽  
Filipe V. Duarte
Keyword(s):  
Tissue Regeneration ◽  
Protein Complexes ◽  
Mitochondrial Protein ◽  
Noncoding Rnas ◽  
Atp Synthesis ◽  
Mitochondrial Proteins ◽  
Cellular Mechanisms ◽  
Small Noncoding Rnas ◽  
Mitochondrial Ribosome

The most famous role of mitochondria is to generate ATP through oxidative phosphorylation, a metabolic pathway that involves a chain of four protein complexes (the electron transport chain, ETC) that generates a proton-motive force that in turn drives the ATP synthesis by the Complex V (ATP synthase). An impressive number of more than 1000 mitochondrial proteins have been discovered. Since mitochondrial proteins have a dual genetic origin, it is predicted that ~99% of these proteins are nuclear-encoded and are synthesized in the cytoplasmatic compartment, being further imported through mitochondrial membrane transporters. The lasting 1% of mitochondrial proteins are encoded by the mitochondrial genome and synthesized by the mitochondrial ribosome (mitoribosome). As a result, an appropriate regulation of mitochondrial protein synthesis is absolutely required to achieve and maintain normal mitochondrial function. Regarding miRNAs in mitochondria, it is well-recognized nowadays that several cellular mechanisms involving mitochondria are regulated by many genetic players that originate from either nuclear- or mitochondrial-encoded small noncoding RNAs (sncRNAs). Growing evidence collected from whole genome and transcriptome sequencing highlight the role of distinct members of this class, from short interfering RNAs (siRNAs) to miRNAs and long noncoding RNAs (lncRNAs). Some of the mechanisms that have been shown to be modulated are the expression of mitochondrial proteins itself, as well as the more complex coordination of mitochondrial structure and dynamics with its function. We devote particular attention to the role of mitochondrial miRNAs and to their role in the modulation of several molecular processes that could ultimately contribute to tissue regeneration accomplishment.

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