[HTML][HTML] DAP5 promotes cap-independent translation of Bcl-2 and CDK1 to facilitate cell survival during mitosis

L Marash, N Liberman, S Henis-Korenblit, G Sivan… - Molecular cell, 2008 - cell.com
L Marash, N Liberman, S Henis-Korenblit, G Sivan, E Reem, O Elroy-Stein, A Kimchi
Molecular cell, 2008cell.com
DAP5 is an eIF4G protein previously implicated in mediating cap-independent translation in
response to cellular stresses. Here we report that DAP5 is crucial for continuous cell survival
in nonstressed cells. The knockdown of endogenous DAP5 induced M phase-specific
caspase-dependent apoptosis. Bcl-2 and CDK1 were identified by two independent screens
as DAP5 translation targets. Notably, the activity of the Bcl-2 IRES was reduced in DAP5
knockdown cells and a selective shift of Bcl-2 mRNA toward light polysomal fractions was …
Summary
DAP5 is an eIF4G protein previously implicated in mediating cap-independent translation in response to cellular stresses. Here we report that DAP5 is crucial for continuous cell survival in nonstressed cells. The knockdown of endogenous DAP5 induced M phase-specific caspase-dependent apoptosis. Bcl-2 and CDK1 were identified by two independent screens as DAP5 translation targets. Notably, the activity of the Bcl-2 IRES was reduced in DAP5 knockdown cells and a selective shift of Bcl-2 mRNA toward light polysomal fractions was detected. Furthermore, a functional IRES was identified in the 5′UTR of CDK1. At the cellular level, attenuated translation of CDK1 by DAP5 knockdown decreased the phosphorylation of its M phase substrates. Ectopic expression of Bcl-2 or CDK1 proteins partially reduced the extent of caspase activation caused by DAP5 knockdown. Thus, DAP5 is necessary for maintaining cell survival during mitosis by promoting cap-independent translation of at least two prosurvival proteins.
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