Role of foam drainage in producing protein aggregates in foam fractionation

Autophagy (self-eating) is an intracellular degradation process used by cells to keep a “clean house”; as it degrades abnormal or damaged proteins and organelles, it helps to fight infections and also provides energy in times of fasting or exercising. Autophagy also plays a role in cancer, although its precise function in each cancer type is still obscure, and whether autophagy plays a protecting (through the clearing of damaged organelles and protein aggregates and preventing DNA damage) or a promoting (by fueling the already stablished tumor) role in cancer remains to be fully characterized. Beclin 1, the mammalian ortholog of yeast Atg6/Vps30, is an essential autophagy protein and has been shown to play a role in tumor suppression. Here, an update of the tumorigenesis regulation by Beclin 1-dependent autophagy is provided.

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Keeping α-Synuclein at Bay: A More Active Role of Molecular Chaperones in Preventing Mitochondrial Interactions and Transition to Pathological States?

Life ◽

10.3390/life10110289 ◽

2020 ◽

Vol 10 (11) ◽

pp. 289

Author(s):

Emelie E. Aspholm ◽

Irena Matečko-Burmann ◽

Björn M. Burmann

Keyword(s):

Molecular Chaperones ◽

Mitochondrial Membrane ◽

Structural Transition ◽

Current Knowledge ◽

Lewy Bodies ◽

Protein Aggregates ◽

Active Role ◽

Proteolytic Processing ◽

Membrane Disruption

The property of molecular chaperones to dissolve protein aggregates of Parkinson-related α-synuclein has been known for some time. Recent findings point to an even more active role of molecular chaperones preventing the transformation of α-synuclein into pathological states subsequently leading to the formation of Lewy bodies, intracellular inclusions containing protein aggregates as well as broken organelles found in the brains of Parkinson’s patients. In parallel, a short motif around Tyr39 was identified as being crucial for the aggregation of α-synuclein. Interestingly, this region is also one of the main segments in contact with a diverse pool of molecular chaperones. Further, it could be shown that the inhibition of the chaperone:α-synuclein interaction leads to a binding of α-synuclein to mitochondria, which could also be shown to lead to mitochondrial membrane disruption as well as the possible proteolytic processing of α-synuclein by mitochondrial proteases. Here, we will review the current knowledge on the role of molecular chaperones in the regulation of physiological functions as well as the direct consequences of impairing these interactions—i.e., leading to enhanced mitochondrial interaction and consequential mitochondrial breakage, which might mark the initial stages of the structural transition of α-synuclein towards its pathological states.

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Theoretical analysis of the performance of a foam fractionation column

Proceedings of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rspa.2013.0625 ◽

2014 ◽

Vol 470 (2165) ◽

pp. 20130625 ◽

Cited By ~ 2

Author(s):

S. T. Tobin ◽

D. Weaire ◽

S. Hutzler

Keyword(s):

Theoretical Analysis ◽

Surfactant Solution ◽

Model System ◽

Foam Fractionation ◽

Fractionation Column ◽

Foam Drainage Equation ◽

Limiting Case ◽

Alternative Set ◽

Theory And Experiment ◽

Foam Drainage

A model system for theory and experiment which is relevant to foam fractionation consists of a column of foam moving through an inverted U-tube between two pools of surfactant solution. The foam drainage equation is used for a detailed theoretical analysis of this process. In a previous paper, we focused on the case where the lengths of the two legs are large. In this work, we examine the approach to the limiting case (i.e. the effects of finite leg lengths) and how it affects the performance of the fractionation column. We also briefly discuss some alternative set-ups that are of interest in industry and experiment, with numerical and analytical results to support them. Our analysis is shown to be generally applicable to a range of fractionation columns.

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Paradoxical Role of Prion Protein Aggregates in Redox-Iron Induced Toxicity

PLoS ONE ◽

10.1371/journal.pone.0011420 ◽

2010 ◽

Vol 5 (7) ◽

pp. e11420 ◽

Cited By ~ 15

Author(s):

Dola Das ◽

Xiu Luo ◽

Ajay Singh ◽

Yaping Gu ◽

Soumya Ghosh ◽

...

Keyword(s):

Prion Protein ◽

Protein Aggregates

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Fusion, fission, and transport control asymmetric inheritance of mitochondria and protein aggregates

The Journal of Cell Biology ◽

10.1083/jcb.201611197 ◽

2017 ◽

Vol 216 (8) ◽

pp. 2481-2498 ◽

Cited By ~ 17

Author(s):

Stefan Böckler ◽

Xenia Chelius ◽

Nadine Hock ◽

Till Klecker ◽

Madita Wolter ◽

...

Keyword(s):

Protein Aggregates ◽

Asymmetric Division ◽

Cell Organelles ◽

Mitochondrial Transport ◽

Daughter Cells ◽

Transport Control ◽

Live Cell Microscopy ◽

Mitochondrial Distribution ◽

Cell Microscopy

Partitioning of cell organelles and cytoplasmic components determines the fate of daughter cells upon asymmetric division. We studied the role of mitochondria in this process using budding yeast as a model. Anterograde mitochondrial transport is mediated by the myosin motor, Myo2. A genetic screen revealed an unexpected interaction of MYO2 and genes required for mitochondrial fusion. Genetic analyses, live-cell microscopy, and simulations in silico showed that fused mitochondria become critical for inheritance and transport across the bud neck in myo2 mutants. Similarly, fused mitochondria are essential for retention in the mother when bud-directed transport is enforced. Inheritance of a less than critical mitochondrial quantity causes a severe decline of replicative life span of daughter cells. Myo2-dependent mitochondrial distribution also is critical for the capture of heat stress–induced cytosolic protein aggregates and their retention in the mother cell. Together, these data suggest that coordination of mitochondrial transport, fusion, and fission is critical for asymmetric division and rejuvenation of daughter cells.

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A model system for foam fractionation

Proceedings of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rspa.2012.0727 ◽

2013 ◽

Vol 469 (2154) ◽

pp. 20120727 ◽

Cited By ~ 2

Author(s):

S. Hutzler ◽

S. T. Tobin ◽

A. J. Meagher ◽

A. Marguerite ◽

D. Weaire

Keyword(s):

Theoretical Analysis ◽

Surfactant Solution ◽

Model System ◽

Foam Fractionation ◽

Numerical Computations ◽

Foam Drainage Equation ◽

Theory And Experiment ◽

Foam Drainage

A model system for theory and experiment that is relevant to foam fractionation consists of a column of foam moving through an inverted U-tube between two pools of surfactant solution. The foam drainage equation and its variants are used for a theoretical analysis of this process. In the limit in which the lengths of the two legs is large , exact analytic formulae may be derived for the key properties of the system. Numerical computations and experiments support these results.

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Role of Hsp104 in the Propagation and Inheritance of the [Het-s] Prion

Molecular Biology of the Cell ◽

10.1091/mbc.e07-07-0657 ◽

2007 ◽

Vol 18 (12) ◽

pp. 4803-4812 ◽

Cited By ~ 21

Author(s):

Laurent Malato ◽

Suzana Dos Reis ◽

Laura Benkemoun ◽

Raimon Sabaté ◽

Sven J. Saupe

Keyword(s):

Meiotic Drive ◽

Protein Aggregates ◽

Propagation Rate ◽

Podospora Anserina ◽

Wild Type ◽

Prion Propagation ◽

Meiotic Instability

The chaperones of the ClpB/HSP100 family play a central role in thermotolerance in bacteria, plants, and fungi by ensuring solubilization of heat-induced protein aggregates. In addition in yeast, Hsp104 was found to be required for prion propagation. Herein, we analyze the role of Podospora anserina Hsp104 (PaHsp104) in the formation and propagation of the [Het-s] prion. We show that ΔPaHsp104 strains propagate [Het-s], making [Het-s] the first native fungal prion to be propagated in the absence of Hsp104. Nevertheless, we found that [Het-s]-propagon numbers, propagation rate, and spontaneous emergence are reduced in a ΔPaHsp104 background. In addition, inactivation of PaHsp104 leads to severe meiotic instability of [Het-s] and abolishes its meiotic drive activity. Finally, we show that ΔPaHSP104 strains are less susceptible than wild type to infection by exogenous recombinant HET-s(218–289) prion amyloids. Like [URE3] and [PIN+] in yeast but unlike [PSI+], [Het-s] is not cured by constitutive PaHsp104 overexpression. The observed effects of PaHsp104 inactivation are consistent with the described role of Hsp104 in prion aggregate shearing in yeast. However, Hsp104-dependency appears less stringent in P. anserina than in yeast; presumably because in Podospora prion propagation occurs in a syncitium.

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