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- Title
Effect of molecular chaperones on aberrant protein oligomers in vitro: super-versus sub-stoichiometric chaperone concentrations.
- Authors
Cappelli, Sara; Penco, Amanda; Mannini, Benedetta; Cascella, Roberta; Wilson, Mark R.; Ecroyd, Heath; Li, Xinyi; Buxbaum, Joel N.; Dobson, Christopher M.; Cecchi, Cristina; Relini, Annalisa; Chiti, Fabrizio
- Abstract
Living systems protect themselves from aberrant proteins by a network of chaperones. We have tested in vitro the effects of different concentrations, ranging from 0 to 16 μm, of two molecular chaperones, namely αB-crystallin and clusterin, and an engineered monomeric variant of transthyretin (M-TTR), on the morphology and cytotoxicity of preformed toxic oligomers of HypF-N, which represent a useful model of misfolded protein aggregates. Using atomic force microscopy imaging and static light scattering analysis, all were found to bind HypF-N oligomers and increase the size of the aggregates, to an extent that correlates with chaperone concentration. SDS-PAGE profiles have shown that the large aggregates were predominantly composed of the HypF-N protein. ANS fluorescence measurements show that the chaperone-induced clustering of HypF-N oligomers does not change the overall solvent exposure of hydrophobic residues on the surface of the oligomers. αB-crystallin, clusterin and M-TTR can diminish the cytotoxic effects of the HypF-N oligomers at all chaperone concentration, as demonstrated by MTT reduction and Ca2+ influx measurements. The observation that the protective effect is primarily at all concentrations of chaperones, both when the increase in HypF-N aggregate size is minimal and large, emphasizes the efficiency and versatility of these protein molecules.
- Subjects
MOLECULAR chaperones; PROTEINS; OLIGOMERS; TRANSTHYRETIN; ATOMIC force microscopy
- Publication
Biological Chemistry, 2016, Vol 397, Issue 5, p401
- ISSN
1431-6730
- Publication type
Article
- DOI
10.1515/hsz-2015-0250