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Comparative analysis of the cytotoxicity of homopolymeric amino acids.

Comparative analysis of the cytotoxicity of homopolymeric amino acids.

Authors :
Oma Y
Kino Y
Sasagawa N
Ishiura S
Source :
Biochimica et biophysica acta [Biochim Biophys Acta] 2005 May 15; Vol. 1748 (2), pp. 174-9. Date of Electronic Publication: 2005 Jan 27.
Publication Year :
2005

Abstract

Many human proteins have homopolymeric amino acid (HPAA) tracts, although the physiological significance or cellular effects of their presence is poorly understood. We previously reported that 20 kinds of HPAAs show characteristic intracellular localization and that among those, hydrophobic HPAAs aggregate strongly and form high molecular weight proteins when expressed in cultured cells. In this study, we investigated the cytotoxicity of 20 kinds of HPAAs. HPAA tracts of approximately 30 residues fused to the C-terminus of YFP were expressed in COS-7 cells. Cells expressing homopolymeric-Cys, -Ile, -Leu, and -Val showed low viability in Trypan Blue assay. Caspase-3 activity, which is usually upregulated in dying cells, was determined by measuring the cleavage of the peptide substrate Ac-DEVD-MCA and by detecting the cleaved active form of the caspase-3 by Western blotting. The activity of caspase-3 was drastically elevated in cells expressing those HPAAs which showed low viability in Trypan Blue assay. Interestingly, it was found that there is a correlation between the hydrophobicity of a single amino acid and the cytotoxicity of the corresponding HPAA as a homopolymer. These results indicate that the hydrophobicity of HPAAs may cause cytotoxicity.

Details

Language :
English
ISSN :
0006-3002
Volume :
1748
Issue :
2
Database :
MEDLINE
Journal :
Biochimica et biophysica acta
Publication Type :
Academic Journal
Accession number :
15769594
Full Text :
https://doi.org/10.1016/j.bbapap.2004.12.017