scholarly journals Role of mitochondria in the pheromone- and amiodarone-induced programmed death of yeast

2005 ◽  
Vol 168 (2) ◽  
pp. 257-269 ◽  
Author(s):  
Andrei I. Pozniakovsky ◽  
Dmitry A. Knorre ◽  
Olga V. Markova ◽  
Anthony A. Hyman ◽  
Vladimir P. Skulachev ◽  
...  
Keyword(s):  
Mitochondrial Protein ◽  
Chain Complex ◽  
Energy Coupling ◽  
Complex Iii ◽  
Strong Increase ◽  
Cytochrome C Release ◽  
Yeast Saccharomyces Cerevisiae ◽  
High Doses ◽  
Multicellular Organisms

Although programmed cell death (PCD) is extensively studied in multicellular organisms, in recent years it has been shown that a unicellular organism, yeast Saccharomyces cerevisiae, also possesses death program(s). In particular, we have found that a high doses of yeast pheromone is a natural stimulus inducing PCD. Here, we show that the death cascades triggered by pheromone and by a drug amiodarone are very similar. We focused on the role of mitochondria during the pheromone/amiodarone-induced PCD. For the first time, a functional chain of the mitochondria-related events required for a particular case of yeast PCD has been revealed: an enhancement of mitochondrial respiration and of its energy coupling, a strong increase of mitochondrial membrane potential, both events triggered by the rise of cytoplasmic [Ca2+], a burst in generation of reactive oxygen species in center o of the respiratory chain complex III, mitochondrial thread-grain transition, and cytochrome c release from mitochondria. A novel mitochondrial protein required for thread-grain transition is identified.

The yeast CBP1 gene produces two differentially regulated transcripts by alternative 3'-end formation

1989 ◽  
Vol 9 (10) ◽  
pp. 4161-4169
Author(s):  
S A Mayer ◽  
C L Dieckmann
Keyword(s):  
Carbon Source ◽  
Cytochrome B ◽  
Mitochondrial Protein ◽  
Nuclear Gene ◽  
Chain Complex ◽  
Complex Iii ◽  
Yeast Cells ◽  
Transcriptional Level ◽  
Amino Acid Residues ◽  
Gene Encoding

CBP1 is a yeast nuclear gene encoding a mitochondrial protein that stabilizes the 5' end of cytochrome b (cob) pre-mRNA. Cytochrome b is the only mitochondrially synthesized component of the respiratory chain complex III. Since the nuclearly encoded subunits of this complex are regulated at the transcriptional level by catabolite repression, we hypothesized that CBP1 might be similarly regulated. To test the idea that transcriptional regulation of CBP1 could coordinate an increase in cytochrome b mRNA stability with an increase in nuclearly encoded complex III subunit production, we characterized the change in abundance of CBP1 mRNA during derepression on a nonfermentable carbon source. Poly(A)+ RNA from derepressed yeast cells was examined by Northern (RNA) analyses with cRNA probes from CBP1. Both 2.2- and 1.3-kilobase (kb) transcripts were detected. The 1.3-kb mRNA lacked approximately 900 nucleotides of the 3' end of the 2.2-kb mRNA, which encodes the carboxyl-terminal 250 amino acid residues of the CBP1 coding sequence. Northern analyses of RNA isolated from deletion-insertion mutants of CBP1 and from strains that overexpress CBP1 mRNA demonstrated that both mRNAs were transcribed from the CBP1 gene. Furthermore, we demonstrated that the levels of the two CBP1 mRNAs were reciprocally regulated by the carbon source in the growth medium. This is the first description of a yeast gene from which two transcripts that can encode proteins with distinctly different coding properties are generated by alternative 3'-end formation.

scholarly journals The yeast CBP1 gene produces two differentially regulated transcripts by alternative 3'-end formation.

1989 ◽  
Vol 9 (10) ◽  
pp. 4161-4169 ◽  
Author(s):  
S A Mayer ◽  
C L Dieckmann
Keyword(s):  
Carbon Source ◽  
Cytochrome B ◽  
Mitochondrial Protein ◽  
Nuclear Gene ◽  
Chain Complex ◽  
Complex Iii ◽  
Yeast Cells ◽  
Transcriptional Level ◽  
Amino Acid Residues ◽  
Gene Encoding

CBP1 is a yeast nuclear gene encoding a mitochondrial protein that stabilizes the 5' end of cytochrome b (cob) pre-mRNA. Cytochrome b is the only mitochondrially synthesized component of the respiratory chain complex III. Since the nuclearly encoded subunits of this complex are regulated at the transcriptional level by catabolite repression, we hypothesized that CBP1 might be similarly regulated. To test the idea that transcriptional regulation of CBP1 could coordinate an increase in cytochrome b mRNA stability with an increase in nuclearly encoded complex III subunit production, we characterized the change in abundance of CBP1 mRNA during derepression on a nonfermentable carbon source. Poly(A)+ RNA from derepressed yeast cells was examined by Northern (RNA) analyses with cRNA probes from CBP1. Both 2.2- and 1.3-kilobase (kb) transcripts were detected. The 1.3-kb mRNA lacked approximately 900 nucleotides of the 3' end of the 2.2-kb mRNA, which encodes the carboxyl-terminal 250 amino acid residues of the CBP1 coding sequence. Northern analyses of RNA isolated from deletion-insertion mutants of CBP1 and from strains that overexpress CBP1 mRNA demonstrated that both mRNAs were transcribed from the CBP1 gene. Furthermore, we demonstrated that the levels of the two CBP1 mRNAs were reciprocally regulated by the carbon source in the growth medium. This is the first description of a yeast gene from which two transcripts that can encode proteins with distinctly different coding properties are generated by alternative 3'-end formation.

Baicalein Protects Cardiomyocytes Against Mitochondrial Oxidant Injury Associated with JNK Inhibition and Mitochondrial Akt Activation

2014 ◽  
Vol 42 (01) ◽  
pp. 79-94 ◽  
Author(s):  
Hsien-Hao Huang ◽  
Zuo-Hui Shao ◽  
Chang-Qing Li ◽  
Terry L. Vanden Hoek ◽  
Jing Li
Keyword(s):  
Cell Death ◽  
Chain Complex ◽  
Complex Iii ◽  
Text Generation ◽  
Oxidant Injury ◽  
Cytochrome C Release ◽  
Scutellaria Baicalensis Georgi ◽  
Akt Phosphorylation ◽  
Dna Laddering ◽  
Mitochondrial Superoxide

Baicalein, a flavonoid derived from Scutellaria baicalensis Georgi, possesses cardioprotection against oxidant injury by scavenging reactive oxygen species (ROS). Few studies investigate whether baicalein protection is mediated by attenuating mitochondrial ROS and modulating the prosurvival and proapoptotic signaling. Primary cultured chick cardiomyocytes were used to study the role of baicalein in mitochondrial superoxide [Formula: see text] generation and signaling of Akt and JNK. Cells were exposed to H 2 O 2 for 2 h and baicalein was given 2 h prior to and during 2 h of H 2 O 2 exposure. Cell viability was assessed by propidium iodide and DNA fragmentation. H 2 O 2 (500 μM) significantly induced 45.3 ± 6.2% of cell death compared to the control (p < 0.001) and resulted in DNA laddering. Baicalein (10, 25 or 50 μM) dose-dependently reduced the cell death to 38.7 ± 5.6% (p = 0.226); 31.2 ± 3.9% (p < 0.01); 30.3 ± 5.3% (p < 0.01), respectively. It also attenuated DNA laddering. Further, baicalein decreased intracellular ROS and mitochondrial [Formula: see text] generation that was confirmed by superoxide dismutase PEG-SOD and mitochondria electron transport chain complex III inhibitor stigmatellin. In addition, baicalein increased Akt phosphorylation and decreased JNK phosphorylation in H 2 O 2-exposed cells. Moreover, baicalein augmented mitochondrial phosphorylation of Akt Thr308 and GSK3β Ser9, and prevented mitochondrial cytochrome c release assessed by cellular fractionation. Our results suggest that baicalein cardioprotection may involve an attenuation of mitochondrial [Formula: see text] and an increase in mitochondrial phosphorylation of Akt and GSK3β while decreasing JNK activation.

scholarly journals Modelling of BCS1L-related human mitochondrial disease in Drosophila melanogaster

2021 ◽  
Author(s):  
Michele Brischigliaro ◽  
Elena Frigo ◽  
Samantha Corrà ◽  
Cristiano De Pittà ◽  
Ildikò Szabò ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Mitochondrial Disease ◽  
Clinical Symptoms ◽  
Genetic Manipulation ◽  
Chain Complex ◽  
Mitochondrial Diseases ◽  
Mitochondrial Respiratory Chain ◽  
Complex Iii ◽  
Mitochondrial Respiratory Chain Complex

AbstractMutations in BCS1L are the most frequent cause of human mitochondrial disease linked to complex III deficiency. Different forms of BCS1L-related diseases and more than 20 pathogenic alleles have been reported to date. Clinical symptoms are highly heterogenous, and multisystem involvement is often present, with liver and brain being the most frequently affected organs. BCS1L encodes a mitochondrial AAA + -family member with essential roles in the latest steps in the biogenesis of mitochondrial respiratory chain complex III. Since Bcs1 has been investigated mostly in yeast and mammals, its function in invertebrates remains largely unknown. Here, we describe the phenotypical, biochemical and metabolic consequences of Bcs1 genetic manipulation in Drosophila melanogaster. Our data demonstrate the fundamental role of Bcs1 in complex III biogenesis in invertebrates and provide novel, reliable models for BCS1L-related human mitochondrial diseases. These models recapitulate several features of the human disorders, collectively pointing to a crucial role of Bcs1 and, in turn, of complex III, in development, organismal fitness and physiology of several tissues.

Collagen-Induced Platelet Aggregation: -Evidence Against the Essential Role of Platelet Adenosine Diphosphate

1979 ◽  
Vol 42 (04) ◽  
pp. 1193-1206 ◽  
Author(s):  
Barbara Nunn
Keyword(s):  
Platelet Aggregation ◽  
Time Course ◽  
Essential Role ◽  
Atp Release ◽  
Adenosine Diphosphate ◽  
Human Platelets ◽  
High Doses ◽  
Induced Aggregation

SummaryThe hypothesis that platelet ADP is responsible for collagen-induced aggregation has been re-examined. It was found that the concentration of ADP obtaining in human PRP at the onset of aggregation was not sufficient to account for that aggregation. Furthermore, the time-course of collagen-induced release in human PRP was the same as that in sheep PRP where ADP does not cause release. These findings are not consistent with claims that ADP alone perpetuates a collagen-initiated release-aggregation-release sequence. The effects of high doses of collagen, which released 4-5 μM ADP, were not inhibited by 500 pM adenosine, a concentration that greatly reduced the effect of 300 μM ADP. Collagen caused aggregation in ADP-refractory PRP and in platelet suspensions unresponsive to 1 mM ADP. Thus human platelets can aggregate in response to collagen under circumstances in which they cannot respond to ADP. Apyrase inhibited aggregation and ATP release in platelet suspensions but not in human PRP. Evidence is presented that the means currently used to examine the role of ADP in aggregation require investigation.

Role of Transcriptional Read-Through in PRE Activity in Drosophila melanogaster

Acta Naturae ◽  
2016 ◽  
Vol 8 (2) ◽  
pp. 79-86 ◽  
Author(s):  
P. V. Elizar’ev ◽  
D. V. Lomaev ◽  
D. A. Chetverina ◽  
P. G. Georgiev ◽  
M. M. Erokhin
Keyword(s):  
Dna Sequences ◽  
Cell Types ◽  
Transcription Terminator ◽  
Response Elements ◽  
Polycomb Response Elements ◽  
The Individual ◽  
Multicellular Organisms ◽  
Different Cell Types ◽  
Main Factor

Maintenance of the individual patterns of gene expression in different cell types is required for the differentiation and development of multicellular organisms. Expression of many genes is controlled by Polycomb (PcG) and Trithorax (TrxG) group proteins that act through association with chromatin. PcG/TrxG are assembled on the DNA sequences termed PREs (Polycomb Response Elements), the activity of which can be modulated and switched from repression to activation. In this study, we analyzed the influence of transcriptional read-through on PRE activity switch mediated by the yeast activator GAL4. We show that a transcription terminator inserted between the promoter and PRE doesnt prevent switching of PRE activity from repression to activation. We demonstrate that, independently of PRE orientation, high levels of transcription fail to dislodge PcG/TrxG proteins from PRE in the absence of a terminator. Thus, transcription is not the main factor required for PRE activity switch.

scholarly journals Pannexins and Connexins: Their Relevance for Oocyte Developmental Competence

2021 ◽  
Vol 22 (11) ◽  
pp. 5918
Author(s):  
Paweł Kordowitzki ◽  
Gabriela Sokołowska ◽  
Marta Wasielak-Politowska ◽  
Agnieszka Skowronska ◽  
Mariusz T. Skowronski
Keyword(s):  
Assisted Reproductive Technologies ◽  
Mammalian Species ◽  
Atp Release ◽  
Reproductive Technologies ◽  
High Energy ◽  
Developmental Competence ◽  
Physiological Processes ◽  
Protein Group ◽  
Multicellular Organisms

The oocyte is the major determinant of embryo developmental competence in all mammalian species. Although fundamental advances have been generated in the field of reproductive medicine and assisted reproductive technologies in the past three decades, researchers and clinicians are still trying to elucidate molecular factors and pathways, which could be pivotal for the oocyte’s developmental competence. The cell-to-cell and cell-to-matrix communications are crucial not only for oocytes but also for multicellular organisms in general. This latter mentioned communication is among others possibly due to the Connexin and Pannexin families of large-pore forming channels. Pannexins belong to a protein group of ATP-release channels, therefore of high importance for the oocyte due to its requirements of high energy supply. An increasing body of studies on Pannexins provided evidence that these channels not only play a role during physiological processes of an oocyte but also during pathological circumstances which could lead to the development of diseases or infertility. Connexins are proteins that form membrane channels and gap-junctions, and more precisely, these proteins enable the exchange of some ions and molecules, and therefore they do play a fundamental role in the communication between the oocyte and accompanying cells. Herein, the role of Pannexins and Connexins for the processes of oogenesis, folliculogenesis, oocyte maturation and fertilization will be discussed and, at the end of this review, Pannexin and Connexin related pathologies and their impact on the developmental competence of oocytes will be provided.

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.

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