d-Polyglutamine Amyloid Recruits l-Polyglutamine Monomers and Kills Cells
| Autor: | Irene Arduini, Karunakar Kar, Patrick C.A. van der Wel, Kenneth W. Drombosky, Ronald Wetzel |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Amyloid
Protein Conformation Molecular Sequence Data Fibril PC12 Cells Article Protein structure Isomerism Structural Biology Spectroscopy Fourier Transform Infrared medicine Fluorescence microscope Animals Amino Acid Sequence Cytotoxicity Molecular Biology Peptide sequence Chemistry Neurodegeneration food and beverages medicine.disease In vitro Rats Kinetics Huntington Disease Biochemistry Biophysics Peptides |
| Zdroj: | Journal of Molecular Biology. 426:816-829 |
| ISSN: | 0022-2836 |
| DOI: | 10.1016/j.jmb.2013.11.019 |
| Popis: | Polyglutamine (polyQ) amyloid fibrils are observed in disease tissue and have been implicated as toxic agents responsible for neurodegeneration in expanded CAG repeat diseases like Huntington’s disease (HD). Despite intensive efforts, the mechanism of amyloid toxicity remains unknown. As a novel approach to probing polyQ toxicity, we investigate here how some cellular and physical properties of polyQ amyloid vary with the chirality of the glutamine residues in the polyQ. We challenged PC12 cells with small amyloid fibrils composed of either L- or D-polyQ peptides and found that D-fibrils are as cytotoxic as L-fibrils. We also found using fluorescence microscopy that both aggregates effectively seed the aggregation of cell-produced L-polyQ proteins, suggesting a surprising lack of stereochemical restriction in seeded elongation of polyQ amyloid. To investigate this effect further, we studied chemically synthesized D- and L-polyQ in vitro. We found that, as expected, D-polyQ monomers are not recognized by proteins that recognize L-polyQ monomers. However, amyloid fibrils prepared from D-polyQ peptides can efficiently seed the aggregation of L-polyQ monomers in vitro, and vice versa. This result is consistent with our cell results on polyQ recruitment, but is inconsistent with previous literature reports on the chiral specificity of amyloid seeding. This chiral cross-seeding can be rationalized by a model for seeded elongation featuring a “rippled β-sheet” interface between seed fibril and docked monomers of opposite chirality. The lack of chiral discrimination in polyQ amyloid cytotoxicity is consistent with several toxicity mechanisms, including recruitment of cellular polyQ proteins. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect