Amyloid Fibril Formation by Bovine Milk κ-Casein and Its Inhibition by the Molecular Chaperones αS- and β-Casein†

Biochemistry ◽  
2005 ◽  
Vol 44 (51) ◽  
pp. 17027-17036 ◽  
Author(s):  
David C. Thorn ◽  
Sarah Meehan ◽  
Margaret Sunde ◽  
Agata Rekas ◽  
Sally L. Gras ◽  
...  
Keyword(s):  
Molecular Chaperones ◽  
Amyloid Fibril ◽  
Bovine Milk ◽  
Fibril Formation ◽  
Amyloid Fibril Formation

The dissociated form of κ-casein is the precursor to its amyloid fibril formation

2010 ◽  
Vol 429 (2) ◽  
pp. 251-260 ◽  
Author(s):  
Heath Ecroyd ◽  
David C. Thorn ◽  
Yanqin Liu ◽  
John A. Carver
Keyword(s):  
Disulfide Bonds ◽  
Amyloid Fibrils ◽  
Amyloid Fibril ◽  
Bovine Milk ◽  
Fibril Formation ◽  
Native Form ◽  
Amyloid Fibril Formation ◽  
Disulfide Linkages ◽  
Related Proteins

Bovine milk κ-casein forms a self-associating oligomeric micelle-like species, in equilibrium with dissociated forms. In its native form, intra- and inter-molecular disulfide bonds lead to the formation of multimeric species ranging from monomers to decamers. When incubated under conditions of physiological pH and temperature, both reduced and non-reduced κ-casein form highly structured β-sheet amyloid fibrils. We investigated whether the precursor to κ-casein fibril formation is a dissociated state of the protein or its oligomeric micelle-like form. We show that reduced κ-casein is capable of forming fibrils well below its critical micelle concentration, i.e. at concentrations where only dissociated forms of the protein are present. Moreover, by regulating the degree of disulfide linkages, we were able to investigate how oligomerization of κ-casein influences its propensity for fibril formation under conditions of physiological pH and temperature. Thus, using fractions containing different proportions of multimeric species, we demonstrate that the propensity of the disulfide-linked multimers to form fibrils is inversely related to their size, with monomeric κ-casein being the most aggregation prone. We conclude that dissociated forms of κ-casein are the amyloidogenic precursors to fibril formation rather than oligomeric micelle-like species. The results highlight the role of oligomerization and natural binding partners in preventing amyloid fibril formation by disease-related proteins in vivo.

Native disulphide-linked dimers facilitate amyloid fibril formation by bovine milk αS2-casein

2020 ◽  
pp. 106530
Author(s):  
David C. Thorn ◽  
Elmira Bahraminejad ◽  
Aidan B. Grosas ◽  
Tomas Koudelka ◽  
Peter Hoffmann ◽  
...  
Keyword(s):  
Amyloid Fibril ◽  
Bovine Milk ◽  
Fibril Formation ◽  
Amyloid Fibril Formation

Immunocytochemical Localization of Amyloid Protein AA in the “Dense Fibrillar Inclusions” of the Reticuloendothelical Cells

1977 ◽  
Vol 35 ◽  
pp. 438-439
Author(s):  
T. Shirahama ◽  
M. Skinner ◽  
A.S. Cohen
Keyword(s):  
Amyloid Fibril ◽  
Close Association ◽  
Gel Filtration ◽  
Fibril Formation ◽  
Amyloid Protein ◽  
Electron Microscopic ◽  
Amyloid Deposits ◽  
Amyloid Fibril Formation ◽  
Electron Microscopic Technique ◽  
Lysosomal System

A1thought the mechanisms of amyloidogenesis have not been entirely clarified, proteolysis of the parent proteins may be one of the important steps in the amyloid fibril formation. Recently, we reported that "dense fibrillar inclusions" (DFI), which had the characteristics of lysosomes and contained organized fibrillar profiles as well, were observed in the reticuloendothelial cells in close association with the foci of new amyloid deposits. We considered the findings as evidence for the involvement of lysosomal system in amyloid fibril formation (l). In the present study, we attempted to determine the identity of the contents of the DFI by the use of antisera against the amyloid protein (AA) and an immuno-electron microscopic technique.Amyloidosis was induced in CBA/J mice by daily injections of casein (l). AA was isolated from amyloid-laden spleens by gel filtration and antibody to it was produced in rabbits (2). For immunocytochemistry, the unlabeled antibody enzyme method (3) was employed.

Monitoring the prevention of amyloid fibril formation by α-crystallin

FEBS Journal ◽  
2007 ◽  
Vol 274 (24) ◽  
pp. 6290-6304 ◽  
Author(s):  
Agata Rekas ◽  
Lucy Jankova ◽  
David C. Thorn ◽  
Roberto Cappai ◽  
John A. Carver
Keyword(s):  
Amyloid Fibril ◽  
Fibril Formation ◽  
Amyloid Fibril Formation

scholarly journals Polyphosphates induce amyloid fibril formation of α-synuclein in concentration-dependent distinct manners

2021 ◽  
Vol 296 ◽  
pp. 100510
Author(s):  
Keiichi Yamaguchi ◽  
Masatomo So ◽  
César Aguirre ◽  
Kensuke Ikenaka ◽  
Hideki Mochizuki ◽  
...  
Keyword(s):  
Amyloid Fibril ◽  
Fibril Formation ◽  
Amyloid Fibril Formation
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