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Structural Characterization Of Clusterin-Chaperone Client Protein Complexes, Amy Wyatt, Justin Yerbury, Mark Wilson
Structural Characterization Of Clusterin-Chaperone Client Protein Complexes, Amy Wyatt, Justin Yerbury, Mark Wilson
Mark R Wilson
Clusterin (CLU) is a potent extracellular chaperone that inhibits protein aggregation and precipitation otherwise caused by physical or chemical stresses (e.g. heat, reduction). This action involves CLU forming soluble high molecular weight (HMW) complexes with the client protein. Other than their unquantified large size, the physical characteristics of these complexes were previously unknown. In this study, HMW CLU-citrate synthase (CS), HMW CLU-fibrinogen (FGN), and HMW CLU-glutathione S-transferase (GST) complexes were generated in vitro, and their structures studied using size exclusion chromatography (SEC), ELISA, SDS-PAGE, dynamic light scattering (DLS), bisANS fluorescence, and circular dichroism spectrophotometry (CD). Densitometry of …
The Extracellular Chaperone Clusterin Sequesters Oligomeric Forms Of The Amyloid-Beta 1-40 Peptide, Priyanka Narayan, Angel Orte, Richard Clarke, Benedetta Bolognesi, Sharon Hook, Kristina Ganzinger, Sarah Meehan, Mark Wilson, Christopher Dobson, David Klenerman
The Extracellular Chaperone Clusterin Sequesters Oligomeric Forms Of The Amyloid-Beta 1-40 Peptide, Priyanka Narayan, Angel Orte, Richard Clarke, Benedetta Bolognesi, Sharon Hook, Kristina Ganzinger, Sarah Meehan, Mark Wilson, Christopher Dobson, David Klenerman
Mark R Wilson
In recent genome-wide association studies, the extracellular chaperone protein, clusterin, has been identified as a newly-discovered risk factor in Alzheimer's disease. We have examined the interactions between human clusterin and the Alzheimer's disease-associated amyloid-β 1-40 peptide (Aβ 1-40), which is prone to aggregate into an ensemble of oligomeric intermediates implicated in both the proliferation of amyloid fibrils and in neuronal toxicity. Using highly sensitive single-molecule fluorescence methods, we have found that Aβ 1-40 forms a heterogeneous distribution of small oligomers (from dimers to 50-mers), all of which interact with clusterin to form long-lived, stable complexes. Consequently, clusterin is able to …
Amyloid-Β Oligomers Are Sequestered By Both Intracellular And Extracellular Chaperones, P Narayan, Sarah Meehan, John Carver, Mark Wilson, C M Dobson, D Klenerman
Amyloid-Β Oligomers Are Sequestered By Both Intracellular And Extracellular Chaperones, P Narayan, Sarah Meehan, John Carver, Mark Wilson, C M Dobson, D Klenerman
Mark R Wilson
The aberrant aggregation of the amyloid-β peptide into β-sheet rich, fibrillar structures proceeds via a heterogeneous ensemble of oligomeric intermediates that have been associated with neurotoxicity in Alzheimer’s disease (AD). Of particular interest in this context are the mechanisms by which molecular chaperones, part of the primary biological defenses against protein misfolding, influence Aβ aggregation. We have used single-molecule fluorescence techniques to compare the interactions between distinct aggregation states (monomers, oligomers, and amyloid fibrils) of the AD-associated amyloid-β(1–40) peptide, and two molecular chaperones, both of which are upregulated in the brains of patients with AD and have been found colocalized …
Ans Binding Reveals Common Features Of Cytotoxic Amyloid Species, Benedetta Bolognesi, Janet Kumita, Teresa Barros, Elin Esbjorner, Leila Luheshi, Damian Crowther, Mark Wilson, Christopher Dobson, Giorgio Favrin, Justin Yerbury
Ans Binding Reveals Common Features Of Cytotoxic Amyloid Species, Benedetta Bolognesi, Janet Kumita, Teresa Barros, Elin Esbjorner, Leila Luheshi, Damian Crowther, Mark Wilson, Christopher Dobson, Giorgio Favrin, Justin Yerbury
Mark R Wilson
Oligomeric assemblies formed from a variety of disease-associated peptides and proteins have been strongly associated with toxicity in many neurodegenerative conditions, such as Alzheimer's disease. The precise nature of the toxic agents, however, remains still to be established. We show that prefibrillar aggregates of E22G (arctic) variant of the A beta(1-42) peptide bind strongly to 1-anilinonaphthalene 8-sulfonate and that changes in this property correlate significantly with changes in its cytotoxicity. Moreover, we show that this phenomenon is common to other amyloid systems, such as wild-type A beta(1-42), the 159T variant of human lysozyme and an SH3 domain. These findings are …
The Chaperone Action Of Clusterin And Its Putative Role In Quality Control Of Extracellular Protein Folding, Amy Wyatt, Justin Yerbury, Stephen Poon, Rebecca Dabbs, Mark Wilson
The Chaperone Action Of Clusterin And Its Putative Role In Quality Control Of Extracellular Protein Folding, Amy Wyatt, Justin Yerbury, Stephen Poon, Rebecca Dabbs, Mark Wilson
Mark R Wilson
The function(s) of clusterin may depend upon its topological location. A variety of intracellular "isoforms" of clusterin have been reported but further work is required to better define their identity. The secreted form of clusterin has a potent ability to inhibit both amorphous and amyloid protein aggregation. In the case of amorphous protein aggregation, clusterin forms stable, soluble high-molecular-weight complexes with misfolded client proteins. Clusterin expression is increased during many types of physiological and pathological stresses and is thought to function as an extracellular chaperone (EC). The pathology of a variety of serious human diseases is thought to arise as …
Protease Activation Of A2-Macroglobulin Modulates A Chaperone-Like Action With Broad Specificity, Katie French, Justin Yerbury, Mark Wilson
Protease Activation Of A2-Macroglobulin Modulates A Chaperone-Like Action With Broad Specificity, Katie French, Justin Yerbury, Mark Wilson
Mark R Wilson
α2-Macroglobulin (α2M) is a major human blood glycoprotein best known for its ability to inhibit a broad spectrum of proteases by a unique trapping method. This action induces an “activated” conformation of α2M with an exposed binding site for the low density lipoprotein receptor, facilitating clearance of α2M-protease complexes from the body. This report establishes that protease activation also modulates a potent chaperone-like action of α2M which has broad specificity for proteins partly unfolded as a result of heat or oxidative stress. Protease-mediated activation of α2M abolishes its chaperone-like activity. However, native α2M is able to form soluble complexes with …
The Extracellular Chaperone Clusterin Influences Amyloid Formation And Toxicity By Interacting With Pre-Fibrillar Structures, Justin Yerbury, Stephen Poon, Sarah Meehan, Brianna Thompson, Janet Kumita, Christopher Dobson, Mark Wilson
The Extracellular Chaperone Clusterin Influences Amyloid Formation And Toxicity By Interacting With Pre-Fibrillar Structures, Justin Yerbury, Stephen Poon, Sarah Meehan, Brianna Thompson, Janet Kumita, Christopher Dobson, Mark Wilson
Mark R Wilson
Clusterin is an extracellular chaperone present in all disease-associated extracellular amyloid deposits, however, its roles in amyloid formation and protein deposition in vivo are poorly understood. The current study initially aimed to characterise the effects of clusterin on amyloid formation in vitro by a panel of eight protein substrates. Two of the substrates (Alzheimer's beta peptide and a PI3-SH3 domain) were then used in further experiments to examine the effects of clusterin on amyloid cytotoxicity and to probe the mechanism of clusterin action. We show that clusterin exerts potent effects on amyloid formation, the nature and extent of which vary …
The Extracellular Chaperone Clusterin Potently Inhibits Human Lysozyme Amyloid Formation By Interacting With Prefibrillar Species, Mark Wilson, Justin Yerbury, Stephen Poon, Christopher Dobson, C V Robinson, Elise Stewart, Janet Kumita, Mireille Dumoulin, Gemma Caddy, Christine Hagan
The Extracellular Chaperone Clusterin Potently Inhibits Human Lysozyme Amyloid Formation By Interacting With Prefibrillar Species, Mark Wilson, Justin Yerbury, Stephen Poon, Christopher Dobson, C V Robinson, Elise Stewart, Janet Kumita, Mireille Dumoulin, Gemma Caddy, Christine Hagan
Mark R Wilson
We have studied the effects of the extracellular molecular chaperone, clusterin, on the in vitro aggregation of mutational variants of human lysozyme, including one associated with familial amyloid disease. The aggregation of the amyloidogenic variant I56T is inhibited significantly at clusterin-to-lysozyme ratios as low as 1:80 (i.e. one clusterin molecule per 80 lysozyme molecules). Experiments indicate that under the conditions where inhibition of aggregation occurs, clusterin does not bind detectably to the native or fibrillar states, or to the monomeric transient intermediate known to be a key species in the aggregation reaction. Rather, it seems to interact with oligomeric species …
Effects Of Glycosylation On The Structure And Function Of The Extracellular Chaperone Clusterin, Elise Stewart, Andrew Aquilina, Simon B Easterbrook-Smith, D Murphy-Durland, C Jacobsen, S Moestrup, Mark Wilson
Effects Of Glycosylation On The Structure And Function Of The Extracellular Chaperone Clusterin, Elise Stewart, Andrew Aquilina, Simon B Easterbrook-Smith, D Murphy-Durland, C Jacobsen, S Moestrup, Mark Wilson
Mark R Wilson
Clusterin is the first well characterized, constitutively secreted extracellular chaperone that binds to exposed regions of hydrophobicity on non-native proteins. It may help control the folding state of extracellular proteins by targeting them for receptor-mediated endocytosis and intracellular lysosomal degradation. A notable feature of secreted clusterin is its heavy glycosylation. Although carbohydrate comprises approximately 20−25% of the total mass of the mature molecule, its function is unknown. Results from the current study demonstrate that deglycosylation of human serum clusterin had little effect on its overall secondary structure content but produced a small increase in solvent-exposed hydrophobicity and enhanced the propensity …
Amyloid Fibril Formation By Bovine Milk Kappa-Casein And Its Inhibition By The Molecular Chaperones Alpha-S And Beta-Casein, Mark Wilson, David Thorn, Agata Rekas, S. L Gras, Christopher Dobson, Sarah Meehan, Cait Macphee, M Sunde
Amyloid Fibril Formation By Bovine Milk Kappa-Casein And Its Inhibition By The Molecular Chaperones Alpha-S And Beta-Casein, Mark Wilson, David Thorn, Agata Rekas, S. L Gras, Christopher Dobson, Sarah Meehan, Cait Macphee, M Sunde
Mark R Wilson
No abstract provided.
Heat Shock Protein 70 Inhibits Alpha-Synuclein Fibril Formation Via Preferential Binding To Prefibrillar Species, Mark Wilson, M. M. Dedmon, J. Christodoulou, Christopher Dobson
Heat Shock Protein 70 Inhibits Alpha-Synuclein Fibril Formation Via Preferential Binding To Prefibrillar Species, Mark Wilson, M. M. Dedmon, J. Christodoulou, Christopher Dobson
Mark R Wilson
No abstract provided.
The Acute Phase Protein Haptoglobin Is A Mammalian Extracellular Chaperone With An Action Similar To Clusterin, Justin Yerbury, Mark S Rybchyn, Simon B Easterbrook-Smith, C. Henriques, Mark Wilson
The Acute Phase Protein Haptoglobin Is A Mammalian Extracellular Chaperone With An Action Similar To Clusterin, Justin Yerbury, Mark S Rybchyn, Simon B Easterbrook-Smith, C. Henriques, Mark Wilson
Mark R Wilson
Haptoglobin (Hp) is an acidic glycoprotein present in most body fluids of humans and other mammals. Although the functions of Hp are not yet fully understood, the available evidence indicates that it is likely to play an important role in suppressing inflammatory responses. Some earlier work suggested that Hp might be a newly identified member of a small group of extracellular chaperones found at significant levels in human body fluids. Previously, the only well-characterized member of this group was clusterin, which shares functional similarities with the small heat-shock proteins. We report here that Hp specifically inhibited the precipitation of a …
Evidence That Clusterin Has Discrete Chaperone And Ligand Binding Sites, Johnathon Lakins, Stephen Poon, Simon Easterbrook-Smith, John Carver, Martin Tenniswood, Mark Wilson
Evidence That Clusterin Has Discrete Chaperone And Ligand Binding Sites, Johnathon Lakins, Stephen Poon, Simon Easterbrook-Smith, John Carver, Martin Tenniswood, Mark Wilson
Mark R Wilson
Clusterin is the first identified extracellular mammalian chaperone and binds to a wide variety of partly unfolded, stressed proteins. Clusterin also binds to many different unstressed ligands including the cell surface receptor low density lipoprotein receptor-related protein-2 (LRP-2). It is unknown whether clusterin binds to all of these many ligands via one or more binding sites. Furthermore, the region(s) of clusterin involved in these many binding interactions remain to be identified. As part of an investigation of these issues, we expressed recombinant human clusterin in the yeast Pichia pastoris. The resultant protein had variable proteolytic truncations of the C-terminal region …
Clusterin Is An Atp-Independent Chaperone With Very Broad Substrate Specificity That Stabilizes Stressed Proteins In A Folding-Competent State, Stephen Poon, Simon Easterbrook-Smith, Mark Rybchyn, John Carver, Mark Wilson
Clusterin Is An Atp-Independent Chaperone With Very Broad Substrate Specificity That Stabilizes Stressed Proteins In A Folding-Competent State, Stephen Poon, Simon Easterbrook-Smith, Mark Rybchyn, John Carver, Mark Wilson
Mark R Wilson
We recently reported that the ubiquitous, secreted protein clusterin has chaperone activity in vitro [Humphreys et al. (1999) J. Biol. Chem. 274, 6875−6881]. In this study, we demonstrate that clusterin (i) inhibits stress-induced precipitation of a very broad range of structurally divergent protein substrates, (ii) binds irreversibly via an ATP-independent mechanism to stressed proteins to form solubilized high molecular weight complexes, (iii) lacks detectable ATPase activity, (iv) when acting alone, does not effect refolding of stressed proteins in vitro, and (v) stabilizes stressed proteins in a state competent for refolding by heat shock protein 70 (HSP70). Furthermore, we show that, …