EGL-1 BH3 mutants reveal the importance of protein levels and target affinity for cell-killing potency
Publication Year 2008-10, Volume 15, Issue #10, Page 1609-1618
- Journal Title
- CELL DEATH AND DIFFERENTIATION
- Publication Type
- Journal Article
- 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(L) 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(S), 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.
- NATURE PUBLISHING GROUP
- BCL-2 FAMILY-MEMBERS; CAENORHABDITIS-ELEGANS; BH3-ONLY PROTEINS; CED-4; DEATH; APOPTOSIS; COMPLEX; RECOGNITION; ACTIVATION; REGULATORS
- Publisher's Version
- Rights Notice
- Refer to copyright notice on published article.
Creation Date: 2008-10-01 12:00:00Last Modified: 0001-01-01 12:00:00