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Critically impaired protein degradation is discussed to contribute to neurodegenerative disorders, including Parkinson's, Huntington's, Alzheimer's, and motor neuron diseases. Misfolded, aggregated, or surplus... more
Critically impaired protein degradation is discussed to contribute to neurodegenerative disorders, including Parkinson's, Huntington's, Alzheimer's, and motor neuron diseases. Misfolded, aggregated, or surplus proteins are efficiently degraded via distinct protein degradation pathways, including the ubiquitin-proteasome system, autophagy, and vesicular trafficking. These pathways are regulated by covalent modification of target proteins with the small protein ubiquitin and are evolutionary highly conserved from humans to yeast. The yeast Saccharomyces cerevisiae is an established model for deciphering mechanisms of protein degradation, and for the elucidation of pathways underlying programmed cell death. The expression of human neurotoxic proteins triggers cell death in yeast, with neurotoxic protein-specific differences. Therefore, yeast cell death models are suitable for analyzing the role of protein degradation pathways in modulating cell death upon expression of disease-causing proteins. This review summarizes which protein degradation pathways are affected in these yeast models, and how they are involved in the execution of cell death. I will discuss to which extent this mimics the situation in other neurotoxic models, and how this may contribute to a better understanding of human disorders.
For millennia, yeast has been exploited to obtain fermentation products, such as foods and beverages. For c. 50 years, yeast has been an established model organism for basic and applied research, and more specifically, for c. 15 years,... more
For millennia, yeast has been exploited to obtain fermentation products, such as foods and beverages. For c. 50 years, yeast has been an established model organism for basic and applied research, and more specifically, for c. 15 years, this unicellular organism has been applied to dissect molecular mechanisms of cell aging and programmed cell death. In this review, we present an overview of approaches to study cell aging and death in yeast, including lifespan assessments, calorie restriction, cell viability, survival, and death markers.
Mitochondria are essential organelles in cellular metabolism. These organelles are bounded by two membranes, the outer and inner membrane. Especially the inner membrane comprises a high content of proteins, for example, the protein... more
Mitochondria are essential organelles in cellular metabolism. These organelles are bounded by two membranes, the outer and inner membrane. Especially the inner membrane comprises a high content of proteins, for example, the protein complexes of the respiratory chain. High-resolution separation and analysis of such membrane proteins, for example, by two-dimensional gel electrophoresis (2-DE), is hampered by their hydrophobicity and tendency for aggregation. Here, we describe the separation of mitochondrial membrane proteins of Saccharomyces cerevisiae by 16-benzyldimethyl-n-hexadecylammonium chloride/sodium dodecyl sulfate polyacrylamide gel electrophoresis (16-BAC/SDS-PAGE). This method enables the separation of membrane proteins owing to the solubilizing power of the ionic detergents 16-BAC and SDS, respectively. Mitochondria were isolated from yeast cultures by differential centrifugation and were further purified by free flow electrophoresis (FFE) in zone-electrophoretic mode (ZE). Subsequently, membrane proteins from ZE-FFE-purified mitochondria were enriched by carbonate extraction and subjected to 16-BAC/SDS-PAGE. The resulting protein spot patterns were visualized by a highly sensitive fluorescence stain with ruthenium-II-bathophenantroline disulfonate chelate (RuBP), and by colloidal Coomassie staining. Proteins were identified by Maldi-Tof mass spectrometry and peptide mass fingerprinting.
Mitochondrial damage and dysfunction are common hallmarks for neurodegenerative disorders, including Alzheimer, Parkinson, Huntington diseases, and the motor neuron disorder amyotrophic lateral sclerosis. Damaged mitochondria pivotally... more
Mitochondrial damage and dysfunction are common hallmarks for neurodegenerative disorders, including Alzheimer, Parkinson, Huntington diseases, and the motor neuron disorder amyotrophic lateral sclerosis. Damaged mitochondria pivotally contribute to neurotoxicity and neuronal cell death in these disorders, e.g., due to their inability to provide the high energy requirements for neurons, their generation of reactive oxygen species (ROS), and their induction of mitochondrion-mediated cell death pathways. Therefore, in-depth analyses of the underlying molecular pathways, including cellular mechanisms controlling the maintenance of mitochondrial function, is a prerequisite for a better understanding of neurodegenerative disorders. The yeast Saccharomyces cerevisiae is an established model for deciphering mitochondrial quality control mechanisms and the distinct mitochondrial roles during apoptosis and programmed cell death. Cell death upon expression of various human neurotoxic proteins...
... Ralf Braun (University of Bayreuth, Germany) addressed a further neurotoxic protein, TDP-43, which upon overexpression in yeast results in apoptotic and ... devoted – pilgrims decided to travel to Canterbury in the midst of spring:... more
... Ralf Braun (University of Bayreuth, Germany) addressed a further neurotoxic protein, TDP-43, which upon overexpression in yeast results in apoptotic and ... devoted – pilgrims decided to travel to Canterbury in the midst of spring: 'And many little birds make melody/That sleep ...
Mitochondria play crucial roles in programmed cell death and aging. Different stimuli activate distinct mitochondrion-dependent cell death pathways, and aging is associated with a progressive increase in mitochondrial damage, culminating... more
Mitochondria play crucial roles in programmed cell death and aging. Different stimuli activate distinct mitochondrion-dependent cell death pathways, and aging is associated with a progressive increase in mitochondrial damage, culminating in oxidative stress and cellular dysfunction. Mitochondria are highly dynamic organelles that constantly fuse and divide, forming either interconnected mitochondrial networks or separated fragmented mitochondria. These processes are believed to provide a mitochondrial quality control system and enable an effective adaptation of the mitochondrial compartment to the metabolic needs of the cell. The baker's yeast, Saccharomyces cerevisiae, is an established model for programmed cell death and aging research. The present review summarizes how mitochondrial morphology is altered on induction of cell death or on aging and how this correlates with the induction of different cell death pathways in yeast. We highlight the roles of the components of the mitochondrial fusion and fission machinery that affect and regulate cell death and aging.