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EGL-1 BH3 mutants reveal the importance of protein levels and target affinity for cell-killing potency.
- Source :
- Cell Death & Differentiation; Oct2008, Vol. 15 Issue 10, p1609-1618, 10p, 1 Chart, 6 Graphs
- Publication Year :
- 2008
-
Abstract
- Studies of the cell death pathway in the nematode Caenorhabditis elegans provided the first evidence of the evolutionary conservation of apoptosis signalling. Here we show that the worm Bcl-2 homology domain-3 (BH3)-only protein EGL-1 binds mammalian pro-survival proteins very poorly, but can be converted into a high-affinity ligand for Bcl-2 and Bcl-x<subscript>L</subscript> by subtle mutation of the cysteine residue at position 62 within the BH3 domain. A 100-fold increase in affinity was observed following a single atom change (cysteine to serine substitution), and a further 10-fold increase by replacement with glycine. The low affinity of wild-type EGL-1 for mammalian pro-survival proteins and its poor expression correlates with its weak killing activity in mammalian cells whereas the high-affinity C62G mutant is a very potent killer of cells lacking Mcl-1. Cell killing by the C62S mutant with intermediate affinity only occurs when this EGL-1 BH3 domain is placed in a more stable context, namely that of Bim<subscript>S</subscript>, which allows higher expression, though the kinetics of cell death now vary depending on whether Mcl-1 is neutralized by Noxa or genetically deleted. These results demonstrate how levels of BH3-only proteins, target affinity and the spectrum of neutralization of pro-survival proteins all contribute to killing activity.Cell Death and Differentiation (2008) 15, 1609–1618; doi:10.1038/cdd.2008.86; published online 20 June 2008 [ABSTRACT FROM AUTHOR]
- Subjects :
- CAENORHABDITIS elegans
CYSTEINE proteinases
GLYCINE
PROTEINS
CELL death
Subjects
Details
- Language :
- English
- ISSN :
- 13509047
- Volume :
- 15
- Issue :
- 10
- Database :
- Complementary Index
- Journal :
- Cell Death & Differentiation
- Publication Type :
- Academic Journal
- Accession number :
- 34300514
- Full Text :
- https://doi.org/10.1038/cdd.2008.86