GCN2 monitors mRNA translation termination.

Area of Science:

• Molecular Biology
• Cellular Biology
• Genetics

Background:

• Regulation of mRNA translation is crucial for protein synthesis.
• Mechanisms monitoring translation termination are poorly understood.
• Translation initiation and elongation are well-studied regulatory steps.

Purpose of the Study:

• To investigate the cellular response to impaired translation termination.
• To identify surveillance mechanisms that monitor translation termination.
• To understand how translation termination defects impact cellular processes.

Main Methods:

• Utilized an acute protein degradation system.
• Employed phenotypic rescue via ectopic expression.
• Performed ribosome profiling analyses.

Main Results:

• Impaired translation termination rapidly activates GCN2 kinase.
• Activated GCN2 phosphorylates eIF2α, inhibiting translation initiation.
• GCN2 monitors terminating ribosomes, preventing collisions and readthrough.
• This response is conserved across stem/somatic cells and mouse/human cells.

Conclusions:

• A conserved surveillance mechanism monitors translation termination.
• GCN2 plays a key role in detecting and responding to translation termination defects.
• This mechanism prevents potentially harmful cellular consequences of faulty translation termination.